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
Firm and easily moveable.
white, or flesh-colored. It can turn bright red if injured, inflamed, or
Painless (but can be painful if injured or
0.4 in. (1 cm) and 1.6 in. (4 cm) in diameter,
although hormone stimulation or injury may cause a cyst to become
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.
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine