Earth Shoes are among the most distinctive footwear designs of the twentieth century. Their defining feature is the “negative heel”: the heel sits lower than the forefoot, reversing the usual construction of a shoe with an elevated heel. Developed by Danish yoga teacher Anne Kalsø, the design was intended to reproduce walking barefoot in soft sand. Earth Shoes became a 1970s cultural phenomenon associated with natural movement and whole-body wellness. Although the design alters gait and redistributes loading, its therapeutic value is more complex than early advertising suggested. Negative-heel footwear should therefore be understood not as universally healthy or harmful, but as a biomechanical intervention whose effects depend on the wearer, the shoe and the way it is introduced.

Kalsø’s idea reportedly began in Brazil in 1957, where she observed barefoot people walking on beaches. Footprints in yielding sand often leave the heel lower than the toes, and Kalsø believed that reproducing this position could encourage upright posture and more natural movement. After returning to Denmark, she worked with a shoemaker and spent years developing prototypes. Her shoes were sold in Copenhagen during the 1960s before reaching the United States. American distribution began in New York in April 1970, near the first Earth Day, inspiring the name “Kalsø Earth Shoe.” Its broad toe box, low heel and countercultural image suited a generation questioning formal fashion. By the mid-1970s, Earth Shoes had become both a wellness product and a symbol of casual, environmentally conscious living.

In biomechanical terms, a negative heel places the ankle in greater dorsiflexion while standing than a conventional positive-heel shoe. This position may increase tension or demand in the gastrocnemius–soleus complex and Achilles tendon, particularly in people accustomed to raised heels. It can also alter the orientation of the tibia and produce compensatory changes at the knee, hip, pelvis and trunk. Earth Shoes were promoted as encouraging improved posture, strengthening the legs and allowing a heel-to-toe walking pattern resembling barefoot movement. Their typically broad forefoot could also give the toes more room than narrow fashion footwear. These features may feel comfortable to some wearers, especially those who dislike heel elevation or forefoot compression.

However, “natural” is not synonymous with clinically beneficial. Walking on deformable sand is not mechanically identical to walking on a hard surface in a shoe with a permanently elevated forefoot. Sand yields beneath the foot, whereas a shoe sole constrains the relationship between the rearfoot and forefoot. Moreover, human movement is adaptable: changing the pitch of a shoe does not simply reposition the foot but can alter muscle activity, joint moments, cadence and balance throughout the lower limb. The effects of a negative heel must therefore be measured rather than assumed from its resemblance to a footprint.

Research confirms that negative-heel rocker shoes modify gait. Myers and colleagues studied forty healthy adults and found that this footwear increased cadence without significantly changing walking speed or stride length. The largest kinematic changes occurred at the ankle, including increased plantarflexion at terminal stance, while greater hip extension and knee flexion were recorded during mid-stance. The authors also identified changes in joint kinetics and concluded that the shoe significantly altered measures at the ankle, knee and hip. Importantly, several statistically significant effects were small or brief and were not considered clinically significant. This study demonstrates a mechanical effect, but it does not prove that ordinary Earth Shoes prevent pain, correct posture or improve health over the long term.

One potential clinical advantage is pressure redistribution. Rocker-type soles are used in therapeutic footwear to reduce pressure beneath selected areas of the forefoot, particularly the metatarsal heads. Such offloading may be useful for a person with a specific pressure-related problem, including some patients at risk of diabetic ulceration. Yet a prescribed rocker shoe and a lifestyle Earth Shoe are not interchangeable. Therapeutic footwear must be matched to foot shape, sensation, joint mobility and the location of high pressure, often with in-shoe pressure testing. A negative heel that reduces loading in one area may increase it elsewhere. A person with diabetes, neuropathy, vascular disease or previous ulceration should therefore not adopt this footwear as self-treatment.

The main concern is the abrupt transfer of demand to tissues that may not be prepared for it. Someone with limited ankle dorsiflexion, tight calf muscles or Achilles tendinopathy may experience discomfort as the heel is lowered. Excessive or sudden use could aggravate the Achilles tendon, calf or plantar structures, although individual responses vary and direct long-term evidence concerning classic Earth Shoes remains limited. People with unstable balance may also find an unfamiliar sole geometry difficult, while those with certain arthritic conditions or fixed deformities may compensate at the knee or hip. Conversely, wearers who are comfortable in low-drop footwear, have adequate ankle mobility and introduce the shoes gradually may tolerate them well. The decisive issue is not whether negative heels are categorically “good” or “bad,” but whether their loading pattern suits a particular person.

Practical use should be cautious. New wearers can begin with short periods on level ground and increase duration only if comfortable. Pain, persistent calf tightness, poor balance, numbness or a new limp are reasons to stop and seek advice. The shoe should fit securely, provide enough width and depth, and suit the intended activity. It should not be regarded as a cure for back pain, poor posture or foot disease. A podiatrist or physiotherapist can assess ankle range, strength, gait and existing pathology before recommending a major change in heel-to-toe pitch.

The negative-heel Earth Shoe occupies an unusual position between fashion, cultural history and applied biomechanics. Anne Kalsø’s design challenged the dominance of elevated heels and anticipated modern interest in low-drop and anatomically shaped footwear. It may offer comfort, toe space and useful pressure redistribution for selected wearers, but the design also changes ankle, knee and hip mechanics and can increase demands on the calf–Achilles system. Evidence shows that negative-heel shoes affect gait; it does not establish the sweeping wellness claims historically associated with them. Earth Shoes are best viewed as one footwear option rather than a universal route to natural posture. Careful fitting, gradual adaptation and attention to individual clinical needs remain more important than any single theory of shoe design.

References

Hutchins, S., Bowker, P., Geary, N., & Richards, J. (2009). The biomechanics and clinical efficacy of footwear adapted with rocker profiles—evidence in the literature. The Foot, 19(3), 165–170. https://doi.org/10.1016/j.foot.2009.01.001

Kalsø Earth Shoes. (n.d.). The story behind the original wellness shoe. https://kalso.vaangroup.com/

Myers, K. A., Long, J. T., Klein, J. P., Wertsch, J. J., Janisse, D. J., & Harris, G. F. (2006). Biomechanical implications of the negative heel rocker sole shoe: Gait kinematics and kinetics. Gait & Posture, 24(3), 323–330. https://doi.org/10.1016/j.gaitpost.2005.10.006

Wu, W. L., Rosenbaum, D., & Su, F. C. (2004). The effects of rocker sole and SACH heel on kinematics in gait. Medical Engineering & Physics, 26(8), 639–646. https://doi.org/10.1016/j.medengphy.2004.05.003

Plantar warts are benign skin lesions caused by infection with the human papillomavirus (HPV). They develop on the soles of the feet and may be pushed inward by weight-bearing forces, producing a thickened lesion that can resemble a corn or callus. Although some plantar warts are painless and disappear spontaneously, others persist, spread, or cause considerable discomfort during standing and walking. Standard treatments include salicylic acid, cryotherapy, curettage, and other destructive or immunomodulatory methods. Cimetidine, a medicine best known for reducing stomach acid, has also been investigated as an oral treatment for warts. Its use remains controversial because the proposed biological rationale is plausible, but clinical evidence is inconsistent.

Cimetidine is a histamine H2-receptor antagonist traditionally used to treat peptic ulcer disease and gastro-oesophageal reflux. Interest in cimetidine for warts arose from observations that, at doses higher than those normally used for gastric disorders, it might alter immune function. Clearance of HPV depends heavily on cell-mediated immunity. Cimetidine has been proposed to suppress regulatory T-cell activity and enhance immune responses involving interleukin-2 and other cytokines. In theory, this could help the body recognise and eliminate HPV-infected keratinocytes. Unlike destructive treatments, oral cimetidine might act on multiple lesions simultaneously and does not cause the pain, blistering, or local tissue damage associated with cryotherapy or surgery.

Early uncontrolled studies and case reports produced encouraging results, particularly in children and patients with numerous or recalcitrant warts. Reported regimens have commonly involved approximately 20–40 mg/kg per day, up to the prescriber’s maximum dose, for several weeks or months. These findings generated enthusiasm because cimetidine is widely available and usually well tolerated. It appeared especially attractive for children who feared painful procedures and for people with widespread warts that would be impractical to treat individually. However, improvement in an uncontrolled study cannot establish that the medicine caused wart clearance. Warts often resolve naturally as the immune system develops an effective response, making spontaneous resolution a major confounding factor.

More rigorous evidence has been less persuasive. Randomised, placebo-controlled trials have generally failed to demonstrate a clear and consistent advantage for cimetidine over placebo in treating common warts. Reviews of wart therapies therefore do not regard oral cimetidine as a reliably effective first-line treatment. Differences in participant age, wart location, treatment dose, treatment duration, and immune status may partly explain the conflicting results. Some individuals could benefit, but current evidence does not identify them confidently. Evidence specifically concerning plantar warts is also limited; results involving warts on the hands or mixed anatomical sites cannot automatically be applied to lesions exposed to pressure on the foot.

Safety is another important consideration. Cimetidine is generally tolerated, but adverse effects can include headache, dizziness, diarrhoea, nausea, fatigue, and skin rash. Less common effects include confusion, liver abnormalities, breast enlargement, and sexual dysfunction, especially with higher doses or prolonged use. The drug inhibits several hepatic cytochrome P450 enzymes and can increase blood concentrations of medicines such as warfarin, phenytoin, and theophylline. Dosage adjustment may be required in renal impairment. Consequently, high-dose cimetidine should not be started without assessment by a doctor, pharmacist, or qualified prescriber. Its off-label status for warts should also be explained so that patients understand the uncertainty surrounding benefit.

Correct diagnosis is essential before any treatment is chosen. A plantar wart often interrupts normal skin lines and may display pinpoint bleeding or dark dots representing thrombosed capillaries. Nevertheless, corns, calluses, foreign-body reactions, and occasionally malignant lesions can look similar. A podiatrist or medical practitioner should evaluate lesions that are atypical, rapidly changing, bleeding, ulcerated, or resistant to treatment. People with diabetes, peripheral neuropathy, poor circulation, or immunosuppression require particular caution and should avoid unsupervised destructive treatments because injury may heal poorly or become infected.

For most patients, treatments with stronger supporting evidence should be considered first. Regular application of topical salicylic acid, after careful soaking and gentle reduction of excess keratin, remains a common first-line option when it is safe. Cryotherapy may also be offered, although it can be painful and is not consistently superior to salicylic acid for plantar warts. Pressure-relieving padding, suitable footwear, keeping the lesion covered, and avoiding picking may reduce discomfort and transmission. Persistent or troublesome lesions may require specialist assessment and discussion of further options.

Cimetidine offers an interesting systemic and potentially painless approach to plantar warts through its proposed immunomodulatory effects. Positive case reports and uncontrolled studies suggest possible benefit for selected patients, particularly those with multiple or difficult warts. However, better-designed trials have not shown dependable superiority over placebo, and evidence specific to plantar lesions remains weak. Cimetidine should therefore not be presented as a proven routine cure. If considered for a carefully selected patient, it should be prescribed with attention to dosage, kidney function, adverse effects, drug interactions, and informed consent. At present, its most appropriate role is an off-label, secondary option rather than a replacement for established care.

References

• Sterling, J. C., Gibbs, S., Haque Hussain, S. S., Mohd Mustapa, M. F., & Handfield-Jones, S. E. (2014). British Association of Dermatologists’ guidelines for the management of cutaneous warts 2014. British Journal of Dermatology, 171(4), 696–712.
• Lipke, M. M. (2006). An armamentarium of wart treatments. Clinical Medicine & Research, 4(4), 273–293.
• Yilmaz, E., Alpsoy, E., & Basaran, E. (1996). Cimetidine therapy for warts: A placebo-controlled, double-blind study. Journal of the American Academy of Dermatology, 34(6), 1005–1007.
• Rogers, C. J., Gibney, M. D., Siegfried, E. C., Harrison, B. R., & Glaser, D. A. (1999). Cimetidine therapy for recalcitrant warts in adults: Is it any better than placebo? Journal of the American Academy of Dermatology, 41(1), 123–127.

Diabetes mellitus affects far more than blood glucose levels. Over time, persistently elevated blood glucose can damage nerves and blood vessels throughout the body, with the feet being particularly vulnerable. A minor blister, crack or cut that would normally heal without difficulty can progress into infection, ulceration and, in severe cases, amputation. Many of these complications are preventable. For this reason, daily foot care, appropriate footwear, regular professional assessment and effective diabetes management are essential parts of protecting the health, mobility and independence of people with diabetes.

One of the most important threats to diabetic foot health is peripheral neuropathy. Prolonged hyperglycaemia can injure the nerves supplying the feet, reducing the ability to feel pain, pressure, heat and cold. This loss of protective sensation means that a person may not notice a sharp object inside a shoe, a blister caused by friction, a burn from hot water or a wound sustained while walking barefoot. Because pain normally warns people to stop an activity and examine an injury, diminished sensation allows tissue damage to continue. Neuropathy may also contribute to foot deformities. These can concentrate pressure on small areas, increasing the likelihood of callus formation and ulceration.

Diabetes can also reduce circulation. Peripheral arterial disease occurs when arteries supplying the legs and feet become narrowed, commonly through atherosclerosis. Smoking, high blood pressure and abnormal cholesterol levels can compound this risk. Poor blood flow deprives damaged tissues of oxygen, nutrients and immune cells, making wounds slower to heal and infections more difficult to overcome. Typical warning signs may include pain in the calves during walking, cold feet, changes in skin colour or wounds that fail to heal. However, neuropathy can mask discomfort, so serious circulatory disease may be present without obvious pain. This combination of impaired sensation and impaired healing makes apparently insignificant injuries potentially dangerous.

A diabetic foot ulcer often develops through a chain of events rather than a single dramatic injury. Repeated pressure or rubbing may produce a callus, beneath which tissue becomes inflamed and breaks down. Alternatively, a small cut, cracked heel or poorly trimmed nail may provide an entry point for bacteria. If the person cannot feel the injury, it may remain untreated while walking continues to stress the area. Infection can then spread into deeper tissues or bone. Diabetic foot ulcers are associated with hospital admission, prolonged treatment and a substantial risk of lower-limb amputation. They can also restrict work, exercise and social participation. Prevention is therefore safer than treating an advanced wound.

Daily inspection is a simple but powerful preventive measure. A person with diabetes should examine the tops, soles, heels, sides and spaces between the toes every day, using a mirror or assistance from another person if necessary. They should look for cuts, blisters, redness, swelling, calluses, cracks, discharge, colour changes and nail problems. Feet should be washed in lukewarm—not hot—water, dried carefully, especially between the toes, and moisturised to reduce dry, cracked skin. Moisturiser should not be placed between the toes because excess moisture there can encourage fungal infection. Corns and calluses should never be cut away at home or treated with acidic over-the-counter preparations; these can damage healthy skin and should instead be assessed by a suitably qualified clinician.

Nail and skin care also require caution. Toenails should generally be trimmed straight across and filed to remove sharp edges, provided the person can see and reach the feet safely and has no major circulatory, sensory or nail problems. People who have poor vision, reduced sensation, thickened nails, previous ulcers or uncertainty about self-care should seek professional help. Walking barefoot, even indoors, increases the risk of unnoticed punctures, burns and cuts. Before putting on shoes, the inside should be checked for stones, rough seams or folded insoles. Socks should be clean, well fitting and free from constrictive bands.

Appropriate footwear helps distribute pressure and protects the feet from trauma. Shoes should fit the length, width and depth of the foot without squeezing the toes or rubbing prominent areas. New footwear should be worn for short periods initially and the feet checked afterward for redness or blistering. People with deformity, severe neuropathy or previous ulceration may require therapeutic footwear or pressure-relieving insoles. Footwear cannot compensate for an untreated wound: hot, swollen or broken skin requires prompt assessment and may require specialised offloading.

Regular clinical screening identifies risk before a crisis develops. Diabetes reviews should include examination of the skin and nails, assessment of foot shape and footwear, testing for protective sensation, and evaluation of circulation. Follow-up should reflect the person’s risk. Neuropathy, arterial disease, deformity, kidney disease or a previous ulcer or amputation require closer surveillance. Podiatrists, diabetes clinicians, nurses and vascular specialists may contribute to multidisciplinary care.

Good general diabetes management is equally important. Keeping blood glucose within an individually agreed target can reduce the progression of nerve and vascular damage. Controlling blood pressure and cholesterol, avoiding tobacco, maintaining appropriate physical activity and attending regular health reviews further protect circulation and healing. Exercise is valuable, but activities and footwear should be chosen carefully when sensation is reduced or an ulcer is present. Education should be practical and repeated because circumstances and risk can change over time.

Certain warning signs demand urgent attention. A new ulcer, spreading redness, swelling, pus, unpleasant odour, blackened skin, fever or a foot that suddenly becomes hot or changes shape should not be managed by simply “waiting to see.” Prompt medical or podiatric assessment can prevent infection and tissue damage from progressing. Even a painless wound can be serious in a person with neuropathy.

People with diabetes must take particular care of their feet because nerve damage can hide injury while poor circulation can delay healing. Pressure, minor trauma and infection may then combine to produce ulceration and possible amputation. Daily inspection and hygiene, safe nail and skin care, protective well-fitting footwear, regular professional screening and good management of diabetes and cardiovascular risks form an effective prevention strategy. Consistent attention to small changes can preserve not only the feet, but also a person’s mobility, confidence, independence and quality of life.

References

American Diabetes Association Professional Practice Committee. (2024). Retinopathy, neuropathy, and foot care: Standards of Care in Diabetes—2024. Diabetes Care, 47(Supplement 1), S231–S243.

International Working Group on the Diabetic Foot. (2023). IWGDF guidelines on the prevention and management of diabetes-related foot disease. https://iwgdfguidelines.org/

National Institute for Health and Care Excellence. (2019, updated 2023). Diabetic foot problems: Prevention and management (NG19). https://www.nice.org.uk/guidance/ng19

World Health Organization. (2023). Diabetes. https://www.who.int/news-room/fact-sheets/detail/diabetes

Human walking requires the body to move forward while maintaining balance, absorbing impact, and limiting unnecessary energy expenditure. In 1953, Saunders, Inman, and Eberhart proposed a highly influential model describing six biomechanical features that smooth the trajectory of the body’s centre of mass during normal gait. These became known as the classic six determinants of gait: pelvic rotation, pelvic tilt, knee flexion during stance, the ankle mechanism, the foot mechanism, and lateral displacement of the pelvis. The model argued that these coordinated movements reduce excessive vertical and lateral motion of the centre of mass, thereby producing a more efficient gait. Although later research has challenged aspects of this explanation, the six determinants remain valuable for understanding walking and interpreting gait abnormalities.

The first determinant is pelvic rotation in the transverse plane. During walking, the pelvis rotates forward on the side of the advancing limb and backward on the side of the trailing limb. The total excursion is commonly described as approximately 8 degrees, although the amount varies among individuals and with walking speed. Pelvic rotation effectively lengthens the step without requiring an equivalent increase in hip motion. At initial contact, the forward rotation of the pelvis allows the heel to contact the ground farther ahead of the body. According to the classic model, this flattens the arc through which the pelvis travels and reduces the fall of the centre of mass at double support. Pelvic rotation also contributes to coordinated counter-rotation between the pelvis and thorax, assisted by reciprocal arm swing, helping control angular momentum.

The second determinant is pelvic tilt, or pelvic obliquity, in the frontal plane. During single-limb support, the pelvis normally drops slightly on the side of the swinging limb. This controlled descent is restrained primarily by the hip abductors of the stance limb, particularly gluteus medius and gluteus minimus. The classic account suggested that a small pelvic drop lowers the peak height reached by the centre of mass during midstance, reducing its vertical excursion. Excessive pelvic drop, however, may indicate hip-abductor weakness, pain, poor motor control, or structural factors and is associated with a positive Trendelenburg sign. Conversely, a rigidly elevated swing-side pelvis may interfere with foot clearance and increase compensatory movements.

The third determinant is knee flexion during the stance phase. Following initial contact, the knee flexes to approximately 15 degrees during loading response before extending toward midstance. This flexion has several important functions. It helps absorb impact, allows controlled lowering of the body, and prevents the lower limb from behaving as a completely rigid strut. Within the classic model, knee flexion reduces the peak vertical elevation of the centre of mass as the body passes over the supporting foot. Eccentric quadriceps activity controls the motion and prevents the knee from collapsing. A stiff-knee pattern may increase vertical movement and loading, whereas excessive flexion, as seen in crouch gait, increases the muscular demands placed on the quadriceps and can substantially raise energy expenditure.

The fourth determinant, the ankle mechanism, operates mainly during the beginning of stance. At initial contact, the heel acts as a rocker while the ankle plantarflexes in a controlled manner, lowering the forefoot to the ground. Tibialis anterior works eccentrically to regulate this motion and prevent the foot from slapping. As the tibia progresses over the planted foot, controlled ankle movement smooths forward progression and moderates the lowering of the body’s centre of mass. The rounded heel and controlled plantarflexion therefore transform what could be an abrupt collision into a gradual transfer of weight. Impairments such as restricted ankle motion, dorsiflexor weakness, or an inappropriate prosthetic-foot alignment can disrupt this mechanism and provoke compensations elsewhere in the limb.

The fifth determinant is the foot mechanism, which becomes especially important during terminal stance. As the heel rises, the forefoot and metatarsal heads form a pivot, often termed the forefoot rocker. Ankle plantarflexion and movement over the forefoot effectively lengthen the supporting limb as the body moves ahead of it. In the classic theory, this delays and reduces the downward displacement of the centre of mass near the end of stance. The foot must also adapt from a relatively flexible structure for shock attenuation to a more rigid lever for propulsion. Subtalar and midfoot motion, plantar-fascial tension through the windlass mechanism, and activity of the plantarflexor muscles all contribute. Pain, deformity, restricted first metatarsophalangeal-joint dorsiflexion, or loss of plantarflexor strength may compromise this rocker and shorten the opposite step.

The sixth determinant is lateral displacement of the pelvis. Walking alternates the base of support from one foot to the other, so the body’s centre of mass must shift from side to side. Humans limit this movement through a relatively narrow step width, physiological knee valgus, and the orientation of the femur from the wider pelvis toward the knees. These structural relationships position each foot nearer the body’s line of progression and reduce the distance through which the pelvis must move to place the centre of mass over the stance limb. Excessive step width generally increases lateral displacement and may raise energy cost, although it can also improve stability in people with impaired balance.

The six determinants do not function independently. Pelvic, hip, knee, ankle, and foot movements overlap throughout the gait cycle, while muscles provide active control and sensory systems continually regulate balance. Consequently, an impairment in one region can produce compensations in another. Limited ankle dorsiflexion, for example, may encourage early heel rise, knee hyperextension, foot pronation, or altered step length. Clinical gait analysis should therefore examine the whole person rather than interpreting any determinant in isolation.

Modern biomechanics has also revised the original claim that minimizing centre-of-mass displacement necessarily minimizes energy consumption. Experimental studies suggest that some determinants have smaller effects on vertical movement than originally proposed. Pelvic obliquity may even increase vertical excursion under certain conditions, while stance-phase knee flexion is strongly associated with impact attenuation rather than simply flattening the centre-of-mass pathway. Contemporary approaches emphasize step-to-step transitions, collision reduction, pendular exchange of kinetic and potential energy, muscle work, stability, and individual variation. Thus, the classic model is best regarded as a foundational descriptive framework rather than a complete theory of walking economy.

In conclusion, the six determinants of gait describe coordinated pelvic rotation, pelvic tilt, stance-phase knee flexion, ankle and foot rocker mechanisms, and control of lateral pelvic displacement. Together, these features help produce smooth, stable progression and provide a practical vocabulary for assessing pathological gait. Although current evidence questions whether their principal purpose is solely to minimize centre-of-mass movement, their historical and clinical importance remains substantial. Used alongside modern kinetic, muscular, and neuromotor analysis, the classic determinants continue to offer a useful introduction to the complexity of human walking.

References

• Gard, S. A., & Childress, D. S. (1997). The effect of pelvic list on the vertical displacement of the trunk during normal walking. Gait & Posture, 5(3), 233–238.
• Gard, S. A., & Childress, D. S. (1999). The influence of stance-phase knee flexion on the vertical displacement of the trunk during normal walking. Archives of Physical Medicine and Rehabilitation, 80(1), 26–32.
• Perry, J., & Burnfield, J. M. (2010). Gait Analysis: Normal and Pathological Function (2nd ed.). SLACK Incorporated.
• Saunders, J. B. de C. M., Inman, V. T., & Eberhart, H. D. (1953). The major determinants in normal and pathological gait. The Journal of Bone & Joint Surgery, 35-A(3), 543–558.

Calcaneal stress fractures are overuse injuries in which repetitive loading produces microscopic damage within the heel bone faster than normal remodelling can repair it. They are less common than tibial or metatarsal stress fractures, yet they are an important cause of persistent heel pain in runners because early symptoms can resemble plantar fasciopathy, Achilles-related pain or a simple heel bruise. Delayed recognition may allow a bone stress reaction to progress to a visible fracture. Fortunately, most calcaneal stress fractures are considered low-risk injuries and heal with conservative care. Effective management, however, requires more than rest: clinicians and runners must identify the training, biomechanical, nutritional and medical factors that disturbed the balance between load and bone capacity.

Mechanism and Risk Factors

The calcaneus transmits substantial forces at initial contact and helps transfer load from the hindfoot to the forefoot during stance. Running subjects it to repeated compression through ground-reaction forces and the opposing pull of the Achilles tendon and plantar fascia. Bone normally adapts to these demands, but abrupt or excessive loading creates microdamage. When osteoclastic resorption temporarily exceeds new bone formation, a stress reaction may develop and eventually form a fracture line.

A rapid increase in mileage is a classic precipitant, but intensity, hills, speed sessions and training frequency are equally important. Returning too quickly after inactivity, changing to a harder surface, beginning military-style conditioning or making a sudden footwear transition may also increase load. Fatigue can alter running mechanics and reduce muscular shock attenuation. Individual factors include previous bone stress injury, low bone mineral density, inadequate recovery, smoking, certain medications and conditions that impair calcium or vitamin D metabolism.

Low energy availability deserves particular attention. When dietary energy is insufficient for both exercise and normal physiology, hormonal and skeletal health may deteriorate. This process forms part of relative energy deficiency in sport (RED-S) and can affect runners of any sex. Menstrual disturbance in women, reduced libido or testosterone in men, recurrent injuries, weight loss and restrictive eating are warning signs rather than markers of athletic fitness. Older runners and athletes with osteoporosis or systemic illness may sustain an insufficiency-type injury under otherwise ordinary loads.

Clinical Presentation and Diagnosis

The typical symptom is gradually increasing pain beneath or around the heel. Initially, discomfort may occur only near the end of a run and settle with rest. As injury severity increases, pain begins earlier, persists after exercise and may interfere with walking. Examination commonly reveals focal tenderness over the posterior or plantar calcaneus and pain when the medial and lateral sides of the heel are compressed together—the calcaneal squeeze test. Swelling, warmth or an antalgic gait may be present. Nevertheless, no single examination finding is conclusive.

Differential diagnosis is broad. Plantar fasciopathy usually causes medial plantar heel pain that is prominent with the first steps after rest, while Achilles tendinopathy is centred near the tendon insertion or midsubstance. Other possibilities include heel-pad syndrome, retrocalcaneal bursitis, nerve entrapment, inflammatory disease, infection and, less commonly, tumour. A careful history should therefore examine training change, pain behaviour, nutrition, menstrual or endocrine health, medications and previous fractures.

Plain radiographs are normally the first imaging test because they can identify alternative pathology and may later show sclerosis or a fracture line. Early radiographs, however, are frequently normal because bone changes take time to become visible. A normal X-ray must not override a strongly suggestive clinical picture. Magnetic resonance imaging is the preferred confirmatory investigation because it detects marrow oedema and fracture morphology without ionising radiation. Computed tomography can define cortical detail or assess uncertain healing, whereas bone scintigraphy is sensitive but less specific and is now used less often.

Treatment and Rehabilitation

Most calcaneal stress fractures heal without surgery. The immediate priority is to stop running and other painful impact activity. Weight-bearing should be guided by symptoms: a runner who can walk comfortably may need only activity modification and supportive footwear, whereas substantial pain, limping or pain during daily activities may justify a walking boot and temporary use of crutches. Analgesia should be discussed with a clinician; repeated use of non-steroidal anti-inflammatory drugs is sometimes discouraged because of concern about bone healing, although human evidence is not definitive.

Rehabilitation should preserve fitness without repeatedly provoking the injury. Deep-water running, swimming or cycling can be introduced if completely pain-free. Calf, foot and proximal lower-limb strength, balance and movement control should be rebuilt progressively rather than treating the heel in isolation. Clinicians should assess energy intake, protein, calcium and vitamin D, but supplements are not substitutes for adequate nutrition and should target demonstrated deficiency or clinical need. Recurrent injuries, RED-S features or unusual fractures warrant medical investigation, potentially including blood tests and bone-density assessment.

Return to running should be based on function rather than a fixed date. The athlete should first be pain-free in daily life and able to walk briskly, hop and perform relevant strength tasks without symptoms during the activity or the following day. A graded walk–run programme can then begin on level ground, with recovery days between sessions. Duration should increase before speed, hills and consecutive running days. Pain that returns during a session, later that day or the next morning signals that loading has advanced too quickly. Uncomplicated injuries may settle within approximately six to eight weeks, but complete return to previous training often takes longer and varies with injury grade and underlying risk factors.

Prevention and Conclusion

Prevention depends on matching training stress to the runner’s capacity. Mileage and intensity should rise gradually, hard sessions should be separated by recovery, and persistent focal heel pain should not be “run through.” Strength training, sufficient sleep, adequate energy intake and timely replacement of unsuitable footwear can support tissue capacity, although no shoe can compensate for excessive load. Training plans should account for recent illness, inactivity and life stress as well as weekly distance.

Calcaneal stress fractures illustrate the continuum of bone stress injury: a potentially reversible stress reaction can become a fracture if warning symptoms are ignored. Early clinical suspicion, appropriate MRI when required, protection from painful loading and correction of contributing factors usually produce an excellent outcome. For runners, the safest route back is neither prolonged complete inactivity nor a rushed return, but progressive loading guided by symptoms, function and bone health.

References

American Academy of Family Physicians (2003). “Common Stress Fractures.” American Family Physician, 68(8), 1527–1532. https://www.aafp.org/pubs/afp/issues/2003/1015/p1527.html

Mayer, S. W., Joyner, P. W., Almekinders, L. C. and Parekh, S. G. (2014). “Stress Fractures of the Foot and Ankle in Athletes.” Sports Health, 6(6), 481–491. https://pmc.ncbi.nlm.nih.gov/articles/PMC4212349/

Mountjoy, M. et al. (2023). “2023 International Olympic Committee’s consensus statement on Relative Energy Deficiency in Sport (REDs).” British Journal of Sports Medicine, 57, 1073–1097. https://doi.org/10.1136/bjsports-2023-106994

Welck, M. J. et al. (2024). “Stress fractures of the foot—current evidence on management.” Journal of Clinical Orthopaedics and Trauma. https://doi.org/10.1016/j.jcot.2024.102446

Foot orthoses are commonly modified to alter the distribution of plantar pressure and the moments acting across the joints of the foot. One such modification is the cuboid notch, also called a cuboid raise or cuboid pad. Despite the word “notch,” the modification creates a localised elevation beneath the cuboid rather than a hollow for the bone. It may be incorporated intrinsically into the orthotic shell during manufacture or added extrinsically with ethylene-vinyl acetate (EVA), cork, felt, or another padding material. Its intended effect is to provide a targeted reaction force beneath the lateral midfoot.

The anatomical rationale for the modification arises from the cuboid’s position within the lateral column. The cuboid articulates posteriorly with the calcaneus and anteriorly with the fourth and fifth metatarsals. It also contributes to the groove through which the peroneus longus tendon passes before crossing the plantar foot. Consequently, motion or loading around the cuboid can influence lateral-column stability, midtarsal mechanics, and medial forefoot function. A correctly positioned cuboid notch applies force to a relatively small area and may therefore affect both local tissue stress and the rotational tendency of the foot.

Clinicians prescribe the modification for several proposed purposes. A common indication is lateral midfoot pain associated with cuboid syndrome or suspected calcaneocuboid dysfunction. In this setting, the raise is intended to resist painful plantar or eversion movement of the cuboid and improve tolerance of weight-bearing. It may also be used to support a low lateral arch, reduce a sensation of the foot sliding laterally from an orthosis, or complement a device containing strong medial posting or a medial heel skive. Some practitioners employ it to encourage the centre of pressure to move medially during midstance and propulsion. This may promote use of the more efficient “high-gear” propulsive mechanism through the first and second metatarsals rather than continued loading of the lateral forefoot.

The biomechanical effect is not universally supinatory. Because the orthotic reaction force is applied lateral to several joint axes, a cuboid raise may create a pronatory moment at the subtalar or midtarsal joints. It may also plantarflex the fourth and fifth rays and, theoretically, improve the mechanical advantage of peroneus longus in stabilising the first ray. These effects can be useful when an orthosis otherwise shifts load too strongly medially. However, they also explain why the modification is not suitable for every patient with lateral pain. Its action depends on the precise location, height, contour, stiffness, footwear, and individual foot mechanics.

Accurate placement is therefore essential. A pad positioned too far laterally may increase pressure over a tender cuboid or create an unwanted eversion moment. In some cases, placing the apex more plantarmedially beneath the cuboid may better oppose the suspected direction of rotation. The modification should be smoothly contoured rather than abrupt, because a concentrated edge can cause discomfort, blistering, or avoidance gait. Its height is generally introduced conservatively and adjusted according to symptoms and functional response. Shoe depth must also be considered, as the raise occupies volume and may increase dorsal pressure within closely fitting footwear.

A practical advantage of an extrinsic pad is reversibility. Before prescribing a permanent shell modification, a clinician can conduct a treatment-direction test using adhesive felt or temporary padding beneath the corresponding area of the foot or orthosis. Improvement in pain, stability, gait, or a relevant functional task supports proceeding, whereas worsening symptoms indicates that the position, magnitude, or underlying hypothesis should be reconsidered. Once a raise has been moulded into a rigid shell it can be difficult to remove; EVA devices may be ground down, but an added pad is easier to reposition or discard.

The principal limitation of the cuboid notch is the weakness of its evidence base. Published literature describes cuboid syndrome, its proposed mechanisms, and treatments such as manipulation, taping, padding, and activity modification, but direct controlled research on cuboid notches in foot orthoses is lacking. There is no established consensus regarding indications, dimensions, or optimal placement. Clinical claims should therefore be framed as biomechanical hypotheses and experience-based practice rather than proven therapeutic effects. Lateral foot pain also has a broad differential diagnosis, including stress injury, peroneal tendinopathy, calcaneocuboid arthritis, nerve irritation, and fifth-metatarsal pathology; an orthotic modification should not substitute for appropriate assessment.

The cuboid notch is a focused and potentially useful modification for managing selected lateral-column problems or balancing the mechanical effects of an orthosis. Its value lies in the ability to apply a strategically placed plantar reaction force, yet the same force can aggravate symptoms when its direction or magnitude is inappropriate. Careful diagnosis, temporary testing, conservative dosing, accurate fabrication, and follow-up are therefore central to its use. Until stronger research is available, the cuboid notch is best regarded not as a standard correction, but as an individualised clinical trial within a broader management plan.

References

Durall, C. J. (2011). Examination and treatment of cuboid syndrome: A literature review. Sports Health, 3(6), 514–519. https://doi.org/10.1177/1941738111405965

PodiaPaedia. (n.d.). Cuboid notch. https://podiapaedia.org/wiki/foot-orthotics/design-features/lateral-column-support/cuboid-notch/

Crocs have become instantly recognizable footwear. Originally designed as practical boating shoes, they are now worn by children, workers, travelers, and comfort seekers. Their lightweight foam construction, wide shape, ventilation holes attract fans and critics. Yet the most important question is not whether Crocs are fashionable, but whether they are good for the feet. The answer is not simply yes or no for everyone. Crocs can be comfortable and useful in certain situations, but they are not ideal for every person or activity.

One of the main benefits of Crocs is their roomy toe box. Many conventional shoes squeeze the toes together, which can cause rubbing and may aggravate bunions, hammertoes, corns, or ingrown toenails. Crocs generally allow the toes to spread more naturally. This extra space can be helpful for people whose feet swell. Their soft material also reduces pressure against sensitive areas. For someone recovering from minor irritation or completing light tasks at home, this combination of space and softness may provide relief.

Crocs also offer cushioning and shock absorption. Their molded foam soles create a soft surface, making standing or walking on hard floors feel more comfortable. That benefits workers in hospitals, kitchens, and other environments where long periods are spent on concrete or tile. They are also lightweight, so the legs may feel less tired than they would in heavy footwear. Many models are washable and water-resistant, making them convenient where spills, dirt, or moisture are common.

Another advantage is their accessibility. Crocs are easy to put on and remove, which can benefit people with limited mobility, arthritis, back pain. The heel strap can provide more security than an ordinary open-backed clog, although less than a fastened walking shoe. Crocs can also protect the soles from hot pavement, rough ground, and minor household hazards more effectively than going barefoot. Around a pool, campsite, garden, or shared shower, they may therefore be a practical short-term choice.

However, comfort does not automatically mean that a shoe provides adequate support. Their moderately soft, flexible construction may not control foot movement well enough for people who need firm stability. Individuals with flat feet, significant overpronation, plantar fasciitis, or other biomechanical problems may require shoes with more structured arch support and a secure heel counter. Because every foot is different, one person may find Crocs soothing while another develops fatigue or pain. A shoe that feels pleasant for ten minutes may also become uncomfortable after several hours of walking.

The loose fit creates another concern. When Crocs are worn without the heel strap, the toes may curl or grip the shoe to keep it from slipping off. Repeated gripping can overwork small muscles and tendons in the feet and lower legs. The lack of a firmly enclosed heel may also reduce stability, especially when walking quickly, climbing stairs, or moving across uneven ground. Wearing the strap behind the heel and choosing the correct size can improve security, but it cannot transform a casual clog into an athletic shoe.

Crocs are therefore unsuitable for activities that involve running, jumping, rapid changes of direction, or long hikes. Athletic shoes are designed to hold the foot securely and provide support appropriate to repeated impact. Crocs can slide, bend, or catch on surfaces during vigorous movement, increasing the possibility of a stumble or injury. Their ventilation holes expose part of the foot, and their soft uppers provide limited protection from sharp tools, falling objects, or heavy equipment. Consequently, they should not replace protective footwear in workplaces where safety shoes are required.

Hygiene and fit also deserve attention. Although Crocs are easy to wash, feet can still sweat inside their nonporous material, potentially causing odor, friction, or skin irritation. The shoes should be cleaned and allowed to dry, and socks may help during extended wear if they do not make the fit too tight. People with diabetes, poor circulation, reduced sensation, or existing foot wounds should be especially cautious. A spacious shoe may seem safe, but unnoticed rubbing or debris inside it can damage vulnerable skin. Such individuals should seek advice from a podiatrist or other qualified healthcare professional about suitable footwear.

Whether Crocs are good for a particular person ultimately depends on fit, duration, activity, and medical needs. They are often sensible for brief errands, household use, gardening, travel, poolside wear, or work that involves moderate standing without major safety hazards. They may also serve as a comfortable alternative when swollen or sensitive feet cannot tolerate rigid footwear. On the other hand, supportive walking shoes are generally better for long distances, and purpose-built athletic or protective shoes are essential for demanding activities. Rotating between different kinds of well-fitting footwear may prevent the same areas of the feet from being stressed every day.

Crocs can be good for the feet when they are properly fitted and used for appropriate purposes. Their wide toe box, cushioning, low weight, and convenience make them comfortable for many wearers. Nevertheless, their loose heel, limited structure, and inadequate protection restrict their usefulness. They should be viewed as practical casual footwear rather than a universal solution to foot pain. Anyone who experiences persistent discomfort should not rely on a shoe alone to solve the problem, but should obtain professional assessment. Used thoughtfully, Crocs can play a helpful role in a varied footwear collection; used for the wrong activity or worn despite pain, they may create more problems than they prevent.

Modern footwear often asks the human foot to adapt to the shoe rather than requiring the shoe to accommodate the foot. Narrow toe boxes, raised heels and rigid soles can restrict the natural spread and movement of the toes. Correct Toes is a reusable silicone toe spacer designed in response to this problem. Invented by podiatrist Dr Ray McClanahan, the device sits between the toes and gently encourages them toward a wider, more anatomical position. Although it appears simple, Correct Toes represents a broader approach to foot health based on alignment, suitable footwear and gradual restoration of natural movement.

Unlike the foam separators commonly used during pedicures, Correct Toes is intended to be worn during ordinary activity. Its flexible design comes in several sizes and can be used barefoot, over toe socks or inside shoes with sufficient room. The crucial phrase is “sufficient room”: inserting any spacer into a narrow shoe may increase pressure rather than relieve it. Correct Toes therefore works most logically with footwear that has a wide, foot-shaped toe box. The manufacturer claims that this combination allows the toes to splay, encourages foot-muscle activity and may improve comfort, balance and circulation.

The reasoning behind the product begins with the mechanical role of the toes. During standing and walking, the forefoot helps support body weight, maintain balance and propel the body forward. The big toe is particularly important during push-off. When toes are crowded or the big toe angles toward the others, pressure may be distributed less comfortably across the forefoot. By creating space between the toes, a spacer can temporarily alter their position and reduce rubbing. This may benefit people troubled by overlapping toes, corns, calluses or discomfort associated with bunions, also called hallux valgus.

Correct Toes may also encourage users to think more carefully about their shoes and movement habits. A spacer cannot compensate for footwear that continually compresses the foot, just as stretching briefly cannot fully offset an entire day spent in a restrictive position. The device is therefore best understood as one element of a conservative foot-care strategy. Wide footwear, gradual strengthening, appropriate mobility exercises and professional assessment may all be equally important. In this respect, the greatest value of Correct Toes may be both physical and educational: it makes the wearer aware of toe position and the space a functioning foot requires.

Scientific evidence, however, calls for measured expectations. A 2024 systematic review of toe separators found ten eligible studies, with sample sizes ranging from nine to ninety participants. The authors concluded that separators may be valuable in conservative treatment, particularly for hallux valgus and related deformities. Yet the studies varied substantially in device type, material, treatment duration and method of use, while reporting was often incomplete. The review therefore emphasised the need for better research. Its findings support toe spacers as a potentially useful tool, but they do not prove every claim made for Correct Toes specifically.

Independent clinical guidance is similarly cautious. Toe spacers can create temporary room between crowded toes, reduce friction and make standing or walking more comfortable for some people. They should not, however, be presented as a guaranteed cure for bunions or as a substitute for diagnosis and treatment. A structural deformity can involve bones, joints, ligaments, heredity and long-term loading patterns. A soft silicone device is unlikely to reverse all these factors by itself. Symptom relief while the spacer is being worn is plausible; permanent correction is a much stronger claim and is not firmly established.

Safe use depends on patience and fit. New users should begin with short periods and increase wear gradually only if the feet remain comfortable. Pain, numbness, skin irritation, colour change or worsening symptoms are signals to stop. The spacer should not squeeze the toes, and shoes must remain roomy after it is inserted. People with diabetes, reduced sensation, poor circulation, recurring sores or complex foot conditions should consult a qualified health professional before use. Persistent pain, progressive deformity or difficulty walking also deserves assessment by a podiatrist or doctor.

Correct Toes is neither a miracle cure nor merely a wellness gimmick. It is a thoughtfully designed version of a simple orthotic idea: giving compressed toes more space. It also illustrates a principle in preventive health: small changes to everyday environments can sometimes matter more than dramatic interventions. Choosing shoes that permit natural toe movement may be as significant as choosing the spacer itself. For some wearers, it may offer comfort, reduce friction and complement exercises and better footwear. Its limitations are equally important, because current evidence does not justify promises of universal or permanent correction. Used gradually, comfortably and with realistic expectations, Correct Toes can form part of a sensible approach to foot health—one that respects the natural shape of the foot while recognising when professional care is needed.

Sources

1. Correct Toes. “The Original Toe Spacer.” Product information. https://correcttoes.com/products/correct-toes-the-original-toe-spacer
2. Krześniak, H., et al. “Toe Separators as a Therapeutic Tool in Physiotherapy—A Systematic Review.” Journal of Clinical Medicine, 2024, 13(24), 7771. https://doi.org/10.3390/jcm13247771
3. Cleveland Clinic. “What Are Toe Separators? And Will They Help?” https://health.clevelandclinic.org/benefits-of-toe-separators-and-spacers

The COVID-19 pandemic transformed an unfamiliar respiratory infection into one of the most intensively studied diseases in modern history. Although fever, cough, fatigue, and loss of smell quickly became recognized symptoms, doctors also began reporting unusual skin changes. Among the most distinctive were red or purple swellings on the toes—and occasionally the fingers—resembling chilblains caused by exposure to cold. Popularly called “COVID toes,” these lesions attracted attention because they frequently appeared in children and young adults who otherwise felt well and often tested negative for active infection. COVID toes illustrate both the wide-ranging effects of SARS-CoV-2 and the difficulty of proving that a striking clinical pattern has a single cause.

COVID toes are medically described as chilblain-like lesions or pernio-like eruptions. They most commonly affect the tips and upper surfaces of the toes but may also develop along the sides of the feet, on the soles, or on the fingers. Affected areas can become red, pink, or violet and may swell or form raised spots. Some people experience itching, tenderness, burning, or pain, while others notice only a change in appearance. Blisters, small areas of tissue damage, or crusting can occasionally occur. Unlike traditional chilblains, which usually develop after exposure to cold and damp conditions, many pandemic-era cases appeared during warm weather or in people without a history of similar problems.

Reports increased sharply during the first months of the pandemic. Dermatologists in Europe and North America described clusters of young patients with chilblain-like lesions at a time when community transmission of COVID-19 was high. The timing suggested an association with SARS-CoV-2, but an unusual pattern complicated the evidence: many affected people had negative polymerase chain reaction tests and no detectable antibodies. Some had experienced mild respiratory symptoms or contact with an infected person several weeks earlier, whereas others had no known exposure. Consequently, COVID toes became a plausible but sometimes controversial manifestation of infection rather than a simple diagnostic sign.

Several explanations have been proposed. One leading theory involves the body’s interferon response. Interferons are proteins that help cells limit viral replication. Children and younger adults may sometimes produce a rapid and powerful type I interferon response that controls SARS-CoV-2 before it causes severe illness or generates easily measurable antibody levels. That same response may promote inflammation around small blood vessels in the skin, producing chilblain-like lesions. Under this interpretation, COVID toes could be evidence of an effective antiviral defence accompanied by localized inflammation.

Other proposed mechanisms include injury to the lining of small blood vessels, activation of the immune system, and microscopic changes in circulation. SARS-CoV-2 can provoke vascular and inflammatory abnormalities, especially in severe disease, but COVID toes generally occur in people with mild or absent systemic symptoms. The lesions should therefore not automatically be equated with the dangerous blood clots associated with serious COVID-19. Some biopsy studies have found inflammation around small vessels and other changes consistent with chilblains, yet these findings do not by themselves prove that the virus directly invaded the skin.

Researchers have also considered the indirect effects of pandemic life. Lockdowns changed footwear, exercise, heating, stress levels, and exposure to cold floors. People spent more time at home, sometimes barefoot, while heightened awareness encouraged them to seek medical advice for marks that might previously have gone unnoticed. Studies comparing case numbers with infection rates have produced mixed conclusions. In some settings, chilblain-like eruptions rose alongside COVID-19 waves; in others, tests and epidemiological evidence did not support a direct link. It is possible that the label “COVID toes” includes several conditions that look alike but arise through different pathways.

Diagnosis is usually clinical. A healthcare professional examines the lesions and asks about their duration, possible cold exposure, medications, previous chilblains, COVID-19 symptoms, and contact with infected individuals. Depending on the circumstances, testing for active or past SARS-CoV-2 infection may be appropriate, although a negative result does not necessarily settle the question. Doctors may investigate alternative causes when lesions are severe, recurrent, unusually persistent, or accompanied by other symptoms. Conditions such as autoimmune disease, circulation disorders, vasculitis, pressure injuries, and ordinary cold-induced chilblains can resemble COVID toes. Rarely, a skin biopsy or blood tests may be needed.

For most patients, the outlook is reassuring. Lesions commonly resolve without treatment within several weeks, although some persist longer or recur. Keeping the feet comfortably warm and dry, avoiding tight footwear, and resisting scratching can reduce irritation. Moisturizers may protect damaged skin, while a clinician may recommend a topical corticosteroid for significant itching or inflammation. Pain relief can be used when appropriate. Antibiotics do not treat the lesions unless a separate bacterial infection develops, and blood-thinning medication should not be taken merely because the term COVID toes suggests a circulation problem.

Certain warning signs deserve prompt medical attention. These include severe or rapidly increasing pain, spreading redness, pus, fever, blackened skin, numbness, an open wound, or evidence that circulation is impaired. People with diabetes, known vascular disease, immune suppression, or other serious medical conditions should seek advice early. Emergency care is warranted for major COVID-19 symptoms such as difficulty breathing, persistent chest pain, confusion, or bluish discolouration of the face or lips. A person who may be infectious should also follow current public-health guidance concerning testing and contact with others.

The scientific significance of COVID toes extends beyond dermatology. Their emergence demonstrated how networks of clinicians and patients can quickly identify possible manifestations of a new disease. It also showed the limits of observation during a crisis. A sudden rise in reports can reveal a genuine biological phenomenon, but changes in behaviour, awareness, testing, and healthcare access can influence what is counted. Establishing causation requires consistent laboratory, pathological, and epidemiological evidence, not merely a memorable name.

In conclusion, COVID toes are chilblain-like lesions that became widely recognized during the pandemic, especially among younger people with mild or no other symptoms. A strong interferon response and inflammation of small blood vessels offer biologically credible explanations, yet negative tests and competing environmental factors leave important questions unresolved. Most cases are temporary and benign, but careful assessment is valuable when symptoms are severe or atypical. COVID toes remain a useful lesson in medical uncertainty: visible on the skin, scientifically intriguing, and best understood through balanced attention to both emerging evidence and alternative explanations.

Selected References

• Freeman, E. E., et al. “Pernio-like skin lesions associated with COVID-19: A case series of 318 patients from 8 countries.” Journal of the American Academy of Dermatology, 2020.
• Hubiche, T., et al. “Clinical, laboratory, and interferon-alpha response characteristics of patients with chilblain-like lesions during the COVID-19 pandemic.” JAMA Dermatology, 2021.
• American Academy of Dermatology Association. “COVID toes and other rashes COVID-19 may cause.”
• DermNet. “COVID toes and other skin manifestations of COVID-19.”

Painful corns are a common foot problem, particularly among people who wear tight shoes, spend long hours standing, or have toes and joints that rub against footwear. Because a corn may return after it has been filed down or removed, many people believe that it grows from a “root” buried deep in the foot. This is an understandable idea, since a corn often has a firm central core that can feel like a thorn pressing into the skin. Medically, however, corns do not have roots. They recur because the pressure or friction that caused the skin to thicken is still present.

A corn is a small, concentrated area of hardened skin. It develops as a protective response when repeated pressure or rubbing irritates one spot. The outer layer of the skin, called the epidermis, produces extra keratin and becomes thicker. This process is known as hyperkeratosis. Unlike a plant, a corn does not send a root into living tissue, and unlike a wart, it is not caused by a virus. The so-called root is actually a dense, cone-shaped core of compacted keratin. Its pointed end faces inward and may press on sensitive tissue, producing pain when a person walks or wears shoes.

There are several kinds of corns. Hard corns commonly form on the tops or outer sides of toes, where shoes exert pressure. Soft corns usually appear between toes, where moisture keeps the thickened skin pale and rubbery. Tiny “seed” corns may develop on the soles. Corns differ from calluses, which are generally broader, flatter areas of thickened skin. Both are caused by mechanical stress, but a corn’s smaller central core often makes it more sharply painful.

The belief in roots is reinforced by what happens after treatment. Filing, trimming, or using a medicated corn product may remove the visible thick skin and reduce pain. Yet the corn can return within weeks if the same shoe continues to squeeze the toe or if an underlying deformity keeps concentrating body weight in one place. The skin is responding normally to continuing stress: it rebuilds its protective layer. Therefore, recurrence does not mean that a root was left behind. It means the cause was not fully corrected.

Several factors can keep that cause active. Shoes with narrow toe boxes, high heels, stiff seams, or poor cushioning may repeatedly rub the foot. Bunions, hammertoes, prominent joints, and other changes in foot shape can create pressure points even in ordinary footwear. An unusual walking pattern may shift weight onto a small area of the sole. Loss of the natural fat padding under the feet, which can occur with age, may also increase pressure. In some cases, people develop corns because they do not wear socks, their socks bunch up, or their shoes are the wrong size.

Lasting treatment therefore focuses on relieving pressure as well as reducing the thickened skin. Wearing properly fitted shoes with enough width and depth for the toes is often the most important step. Cushioned socks, protective pads, toe sleeves, insoles, or prescribed orthotics may redistribute pressure. A podiatrist can safely pare down thick skin and assess whether a structural or walking problem is contributing. If a significant bunion or toe deformity repeatedly causes severe corns, corrective surgery may occasionally be considered, but most cases are managed without an operation.

Home care should be cautious. After soaking the foot in warm water, a person without circulation or sensation problems may gently use a pumice stone or foot file to reduce hard skin. The aim is gradual smoothing, not digging out a core. Corns should never be cut with a razor, knife, scissors, or other sharp object, because this can cause bleeding, infection, and lasting injury. Pulling at a corn is also unsafe. Moisturizers containing urea may soften thick skin, although product choice should be discussed with a pharmacist or clinician when medical conditions are present.

Over-the-counter corn plasters and liquids often contain salicylic acid, which dissolves keratin. These products can help selected healthy adults, but they may also burn normal skin if applied incorrectly. People with diabetes, poor circulation, reduced feeling in their feet, fragile skin, kidney disease associated with foot complications, or a history of ulcers should not self-treat a corn with acid or sharp instruments. They should seek professional foot care instead. Even a minor wound may be difficult for such individuals to detect or heal.

Correct identification matters because not every painful lump of hard skin is a corn. Plantar warts can resemble corns but are caused by human papillomavirus and may show tiny dark dots where small blood vessels have clotted. A splinter, cyst, ulcer, or other lesion can also be mistaken for one. A clinician should examine any growth that bleeds, changes rapidly, drains fluid, becomes red or swollen, causes intense pain, or does not improve when pressure is removed. Urgent advice is appropriate if there are signs of infection, such as spreading redness, warmth, pus, fever, or red streaks.

The outlook for ordinary corns is generally good. Once the pressure point is removed, the excess keratin can gradually wear away or be safely reduced, and the pain may disappear. Some feet, however, have permanent structural features that make pressure difficult to eliminate completely. In those cases, regular shoe adjustments, padding, podiatry visits, and careful skin maintenance may be needed. This is prevention and management, not an attempt to kill a hidden root.

Painful foot corns do not grow back from roots. The hard central plug is compressed keratin, not a living root, and it cannot regenerate independently. Corns return when repeated pressure or friction prompts the skin to protect itself again. Simply removing the surface thickening may provide temporary relief, but preventing recurrence requires attention to footwear, pressure distribution, foot shape, and walking mechanics. Safe treatment avoids cutting and treats the cause rather than chasing an imaginary root. Anyone with persistent pain, uncertain diagnosis, infection signs, diabetes, poor circulation, or reduced foot sensation should obtain advice from a doctor or podiatrist.