Skin cysts are noncancerous, closed pockets of tissue that can be filled with fluid, pus, or other material.
Cysts are common on the skin and can appear anywhere. They feel like large peas under the surface of the skin. Cysts can develop as a result of infection, clogging of sebaceous glands (oil glands), or around foreign bodies, such as earrings.
Cysts usually do not cause pain unless they rupture or become infected or inflamed. Most cysts do not disappear on their own without treatment. Some cysts may need to be drained to relieve symptoms. That involves piercing the cyst with a scalpel and draining it. That doesn’t cure the cyst, however. Some inflamed cysts can be treated with an injection of cortisone medication to cause it to shrink. Cysts that do not respond to other treatments or reoccur can be removed surgically if they cause troublesome symptoms.