Corns and calluses

What they are

Skin thickens to protect itself from repeated pressure and rubbing. A callus is a broad, flat patch of hard skin, usually under the ball of the foot, on the heel or along the side of the big toe. A corn is a small, concentrated patch with a hard core that presses inward, typically on top of a bent toe, at the tip of a toe, or between two toes where they squeeze together (a “soft corn”). Both can hurt, sometimes a lot, because the thickened skin presses on the tissue beneath.

Why they form

• Shoes that are too tight, too short or too narrow, or high heels that shift weight onto the ball of the foot. In studies, most people were wearing shoes that didn’t match the width or length of their feet, and poor fit was linked to corns and calluses.^[1]
• Toe shape: hammertoes and claw toes rub on shoes on top and press down at the tip. See hammertoes.
• Bunions, which rub on the shoe and shift pressure onto the other toes. See bunions.
• Foot structure, such as a high arch or a prominent metatarsal bone, that concentrates pressure under the ball of the foot. See high-arched feet.
• How you walk, and activities that load one part of the foot again and again.

Corn, callus or wart?

A plantar wart can look like a callus, but it is a viral skin infection that needs different treatment. Warts interrupt the skin lines and show pinpoint bleeding when pared; calluses don’t. Our article plantar wart or callus? explains how to tell, and plantar warts covers treatment.

Treatment at the practice

• Careful trimming (debridement) of the thick skin with a sterile blade. It usually doesn’t hurt, because the skin being removed is dead, and it gives quick relief. In a randomized trial, trimming relieved callus pain more than salicylic acid patches in the first six weeks.^[3] On its own, though, its effect is short-lived: in older adults, trimming was only slightly better than a sham treatment, which is why we combine it with pressure relief.^[6]
• Padding and protection: cushions, toe sleeves and separators that take pressure off a corn or callus. Pads and inserts that spread pressure more evenly have longer-term benefits than medicated products.^[2]
• Inserts and custom orthotics that move pressure away from an overloaded spot under the ball of the foot. See custom orthotics.
• Footwear advice: enough length, width and depth for your feet, and a soft upper over a bent toe or bunion.
• Treating the cause when a corn or callus keeps coming back over the same toe joint or bone, which sometimes means correcting a hammertoe or bunion.

For corns, salicylic acid plasters helped more corns resolve in a large trial, but they didn’t reduce how often corns came back, and corns between and on top of the toes resolved faster than corns on the sole.^[7] That is why lasting relief depends on changing the pressure, not only on removing the hard skin.

Safe home care

• Soak the foot, then gently file thick skin with a pumice stone or foot file. Don’t try to remove it all at once.
• Moisturize dry skin on the heels and soles (not between the toes).
• Use non-medicated pads or toe sleeves to protect a sore spot.
• Don’t cut corns or calluses with razors or scissors.
• If you have diabetes, neuropathy or poor circulation, skip home treatment of corns and calluses and talk with your foot doctor about how to care for them.^[5]

Diabetes, corns and calluses

For someone with diabetes, a thick callus is more than a nuisance. Pressure under a callus can damage the tissue beneath it and turn into an ulcer, and a dark spot of bleeding under a callus is a warning sign. International guidelines on preventing diabetic foot ulcers recommend treating these pre-ulcerative signs promptly and wearing properly fitting, protective footwear.^[4] Regular trimming at the practice is part of routine diabetic foot care. See diabetic foot care.

Common questions

Do corns have roots?

No. The hard core of a corn can feel like a root, but it is simply compressed dead skin pushed inward by pressure. Once the pressure is relieved, it is much less likely to form again.

Are medicated corn pads safe?

They contain salicylic acid, which softens thick skin but can also irritate or damage the healthy skin around a corn. They can help some people, but don’t use them if you have diabetes, neuropathy or poor circulation.^[5]

Why does my callus keep coming back?

Because the pressure that made it is still there. Trimming removes the hard skin, but the skin will build up again until the shoe, the foot mechanics or the bone underneath is addressed.^[6,2]

When to seek care