Epidermoid Cysts

Epidermoid cysts are benign bumps under the outer layer of the skin. These bumps will enlarge slowly over time and should not be painful. They can appear anywhere on the skin but are most common on face, neck, and trunk.


Epidermoid cysts are usually caused by a buildup of keratin, a protein that occurs naturally in skin cells. Cysts develop when the protein is trapped below the skin because of damage to the skin or to a hair follicle. This damage can be caused by acne or excessive exposure to the sun.

Risk Factors

Those who have gone through puberty or have had trouble with acne in the past are more likely to have cysts. Some genetic disorders or skin wounds can also increase the risk of cysts. Damage to the skin can also cause epidermoid cysts.


Cysts can swell and itch and also appear on the skin as a small red bump with a tiny black opening through which an odorous substance can be emitted.


Most don’t cause problems or require treatment but see a doctor if you have one that:

  • Grows fast
  • Ruptures, becomes painful, or gets infected
  • Occurs in an area under constant irritation
  • Bothers you for cosmetic reasons

A doctor should be able to diagnose a cyst by sight, but may need to do a biopsy to diagnose more serious concerns.


Injection into the cyst or drainage of the cyst, as well as laser procedures or surgery are all available treatments for cysts. The treatment for cysts include:

  • Injection
  • Incision and drainage
  • Minor surgery
  • Lasers


There is no way to prevent a cyst from forming.

*Source: Mayo Clinic