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

Q: I recently noticed that I have a cyst. What is the treatment?

A: Slow growing and often painless, cysts rarely cause problems or need treatment. But, you might choose to have a cyst removed by your dermatologist if its appearance bothers you, or to prevent it from becoming painful, ruptured or infected.

There are several forms of treatment:

  • Corticosteroid injection. A cyst that is inflamed, but not uninfected, might be injected with a corticosteroid to reduce inflammation.
  • Incision and drainage. In this procedure, your doctor makes a small cut in the cyst and expresses the contents. Although incision and drainage is relatively quick and easy, cysts often recur after this treatment and they might drain for an extended period of time before they are healed completely.
  • Excision. The cyst can usually be easily removed by a simple operation.

Q: Are there different kinds of cysts?

A: Yes, there are a number of different types of cysts. Here a few:

  • Epidermoid cysts are often called “sebaceous cysts” because they appear very similar and are often treated in the same manner. However, a true sebaceous cyst is less common and arises from cells that make up the sebaceous gland instead of the cells that form the epidermis.
  • Milia are small, scattered epidermoid cysts. They appear like tiny, deep-seated whiteheads that never seem to come to the surface. They’re especially common on the face of infants and older individuals with significant sun damage. They can also be caused or aggravated by long-term use of oil-based creams or cosmetics.
  • Pilar cyst. A small bump that appears on the scalp may look like an epidermoid cyst. It will usually have thicker walls and a different lining than an epidermoid.

Q: What are the symptoms?

A: Cysts can take on several symptoms. Among them are:

  • 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

Q: What causes cysts?

A: The epidermis, the topmost layer of skin, is constantly growing new skin cells and shedding old cells. If these cells grow inward, they cannot shed and start to accumulate under the skin.

This is most likely to occur near small hair follicles and larger oil glands that are concentrated on the face, neck, upper back and groin.

If you have a cyst that is growing in size, painful, ruptured, infected, or you feel is cosmetically unattractive, call a dermatologist.

Dr. Oswald Lightsey Mikell, certified by the American Board of Dermatology and the American Board of Cosmetic Surgery, is the owner of Dermatology Associates of the Lowcountry.