What Are Corns and Calluses?

Corns and calluses are areas of thickened, hardened skin that develop in response to repeated friction or pressure. They are the skin’s protective response to mechanical stress—the keratinocytes (skin cells) multiply and harden to form a protective layer over the area being stressed. While this protective mechanism makes biological sense, the thickened tissue itself becomes painful when it grows large enough to create pressure on the underlying nerves and tissues.

Calluses are diffuse areas of thickened skin that form over broad pressure areas—most commonly the heel, the ball of the foot under the metatarsal heads, and the lateral border of the foot. They are typically not painful unless they become very thick. Corns are smaller, more focal areas of thickened skin with a hard central core (nucleated corn or heloma durum) that concentrates pressure on a small area, making them more acutely painful than diffuse callus. Soft corns (heloma molle) form between the toes where moisture keeps the skin soft; they appear white and macerated and are frequently confused with fungal infection.

Why Do Corns and Calluses Form?

The underlying cause of corn and callus formation is abnormal pressure distribution in the foot. Structural foot problems—bunions, hammertoes, prominent metatarsal heads, flat feet, high-arch feet—create focal pressure areas that drive callus formation. Ill-fitting footwear (too tight, too narrow, or with seams pressing on the toes) is the most common external cause. Activities involving prolonged standing or walking on hard surfaces increase callus formation at weight-bearing areas.

Corns between the toes typically result from bone-to-bone pressure where adjacent toes press against each other—often from an underlying hammertoe deformity or prominent toe condyles. Corns under the metatarsal heads (plantar or intractable plantar keratosis, IPK) develop when a single metatarsal head bears disproportionate weight due to its position or prominence. These plantar corns are particularly painful and frequently require professional treatment rather than home care alone.

Home Treatment

For mild, non-painful calluses, home treatment is appropriate: soak the foot in warm water for 10–15 minutes to soften the skin, then use a pumice stone or foot file to gently reduce the thickened tissue in a circular motion. Apply a thick moisturizing cream (urea cream 10–20%, Flexitol, or AmLactin) to maintain skin pliability and prevent cracking. Shoe padding (moleskin, gel corn pads) can reduce pressure on callus-prone areas. Over-the-counter medicated corn pads containing salicylic acid can soften and reduce corns but should not be used by diabetics, patients with poor circulation, or on irritated or broken skin—the acid can cause chemical burns in vulnerable patients.

Home treatment addresses the symptoms but not the underlying cause. Calluses will recur if the mechanical factors driving their formation (shoe fit, foot structure) are not corrected. Wide, accommodative shoes with soft uppers and adequate depth reduce friction and pressure on at-risk areas. Custom orthotics redistribute metatarsal pressure away from callus-forming areas and are highly effective for recurrent plantar calluses.

Podiatric Treatment

Podiatric treatment for corns and calluses involves sharp debridement—precise removal of the thickened keratinized tissue using a scalpel. This is the fastest and most effective method of reducing painful corns and calluses. The procedure is painless (the thickened tissue has no nerve supply), takes a few minutes in the office, and provides immediate pain relief in most cases. Regular debridement appointments (every 6–10 weeks for recurrent problems) maintain comfort and prevent corns from becoming severely thickened.

For intractable plantar keratosis (discrete plantar corns over prominent metatarsal heads), surgical metatarsal osteotomy or condylectomy may be recommended when conservative measures have failed. These procedures correct the underlying bony prominence that creates the focal pressure point, addressing the cause rather than managing the symptom. For interdigital corns caused by hammertoe deformity, hammertoe correction surgery removes the prominent bone-to-bone contact that generates the corn. A podiatric evaluation can determine whether surgical correction is appropriate based on the severity and impact of the condition.

Frequently Asked Questions

Medical References & Sources

• American Podiatric Medical Association — Corns and Calluses
• PubMed Research — Callus Debridement and Orthotic Offloading
• American Academy of Dermatology — Corns and Calluses

Dr. Tom Biernacki, DPM is a board-certified podiatric surgeon at Balance Foot & Ankle in Howell and Bloomfield Hills, Michigan. He treats corns, calluses, and intractable plantar keratosis with debridement, custom orthotics, and surgical correction of underlying structural deformities.