Epidermal Cyst

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An epidermal cyst, or sebaceous cyst, is a sac beneath the outer layer of the skin that is filled with a cheeselike, greasy material (sebum). These cysts most often appear on the scalp, ears, face, back, or scrotum and are caused by plugged ducts at the site of a hair follicle.

Signs and symptoms include a bump or lump under the skin that is:

  • Firm and easily moveable.
  • Yellow, white, or flesh-colored. It can turn bright red if injured, inflamed, or infected.
  • Painless (but can be painful if injured or infected).
  • Between 0.4 in. (1 cm) and 1.6 in. (4 cm) in diameter, although hormone stimulation or injury may cause a cyst to become larger.

Medical treatment is usually not needed if the cyst does not cause symptoms. A cyst can be removed if its appearance causes embarrassment or if it becomes injured or infected. If the cyst is infected, antibiotics may be used after the cyst is removed.

Current as of: February 20, 2015

Author: Healthwise Staff

Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine