Foot Problems Slideshow Pictures What Feet Say About Health Slideshow Pictures Take the Feet Facts Quiz!

Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What are corns and calluses?

Corns and calluses are annoying and sometimes painful thickenings that form in the skin in areas of pressure. The medical term for the thickened skin that forms corns and calluses is hyperkeratosis. A callus refers to a more diffuse, flattened area of thick skin, while a corn is a thick, localized area that usually has a conical or circular shape. Corns, also known as helomas, sometimes have a dry, waxy, or translucent appearance.

Corns and calluses occur on parts of the feet and sometimes the fingers. Corns can be painful to walk on, even when they are small. Common locations for corns are

• on the sole, over the metatarsal arch (the "ball" of the foot);



• on the outside of the fifth (small or "pinky") toe, where it rubs against the shoe; and



• between the fourth and fifth toes. Unlike other corns that are firm and flesh-colored, corns between the toes are often whitish and messy; they are sometimes called "soft corns" (heloma molles), in contrast to the more common "hard corns" (heloma durums) found in other locations.

Why do corns and calluses develop?

Hyperkeratosis simply means thickening of the skin; this thickening occurs as a natural defense mechanism that strengthens the skin in areas of friction or pressure. Abnormal anatomy of the feet, such as hammer toe or other toe deformities, can lead to corn or callus formation as can bony prominences in the feet. Footwear that is too tight or that exerts friction at specific points can also cause skin thickening that leads to corns and calluses. Abnormalities in gait or movement that result in increased pressure to specific areas can also be the cause.

It can be hard to know why finger corns develop since they often don't appear at sites of obvious pressure. Finger calluses may develop in response to using tools, playing musical instruments, or using work equipment that exerts pressure at specific sites.