Epidermoid cysts (sebaceous cysts)

Epidermoid (ep-ih-DUR-moid) cysts are noncancerous small bumps beneath the skin. Epidermoid cysts can appear anywhere on the skin, but are most common on the face, neck and trunk.

Slow growing and often painless, epidermoid cysts rarely cause problems or need treatment. But you may choose to have a cyst removed by a doctor if its appearance bothers you or if it's painful, ruptured or infected.

Many people refer to epidermoid cysts as sebaceous cysts, but they're different. True sebaceous cysts are less common. They arise from the glands that secrete oily matter that lubricates hair and skin (sebaceous glands).

Symptoms Causes Risk factors Complications

Epidermoid cyst signs and symptoms include:

  • A small, round bump under the skin, usually on the face, trunk or neck
  • A tiny blackhead plugging the central opening of the cyst
  • A thick, yellow, foul-smelling material that sometimes drains from the cyst
  • Redness, swelling and tenderness in the area, if inflamed or infected

When to see a doctor

Most epidermoid cysts don't cause problems or need treatment. See your doctor if you have one that:

  • Grows rapidly
  • Ruptures or becomes painful or infected
  • Occurs in a spot that's constantly irritated
  • Bothers you for cosmetic reasons

© 1998-2015 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of use