You may have a corn or a callus if you notice:

• A thick, rough area of skin
• A hardened, raised bump
• Tenderness or pain under your skin
• Flaky, dry or waxy skin

Corns and calluses are not the same thing.

• Corns are smaller than calluses and have a hard center surrounded by inflamed skin. Corns tend to develop on parts of your feet that don't bear weight, such as the tops and sides of your toes and even between your toes. They can also be found in weight-bearing areas. Corns can be painful when pressed.
• Calluses are rarely painful. They usually develop on the soles of your feet, especially under the heels or balls, on your palms, or on your knees. Calluses vary in size and shape and are often larger than corns.

Pressure and friction from repetitive actions cause corns and calluses to develop and grow. Some sources of this pressure and friction include:

• Wearing ill-fitting shoes. Tight shoes and high heels can compress areas of your feet. When footwear is too loose, your foot may repeatedly slide and rub against the shoe. Your foot may also rub against a seam or stitch inside the shoe.
• Skipping socks. Wearing shoes and sandals without socks can cause friction on your feet. Socks that don't fit properly also can be a problem.
• Playing instruments or using hand tools. Calluses on your hands may result from the repeated pressure of playing instruments, using hand tools or even writing.

These factors may increase your risk of corns and calluses:

• Bunions. A bunion is an abnormal, bony bump that forms on the joint at the base of your big toe.
• Hammertoe. A hammertoe is a deformity in which your toe curls like a claw.
• Other foot deformities. Certain conditions, such as a bone spur, can cause constant rubbing inside your shoe.
• Not protecting your hands. Using hand tools without wearing gloves exposes your skin to excessive friction.