Epidermoid Cysts: How to Spot Them and Treat Them

What They Look Like and When to Get Them Removed

A model of normal human skin.
A model of normal human skin. ericsphotography/Getty Images

An epidermoid cyst is the most common type of skin cyst. These types of cysts can occur anywhere on the body but tend to occur more frequently on the face or upper trunk. Other names for an epidermoid cyst include epidermal cyst, infundibular cyst, epidermal inclusion cyst, keratin cyst, and sebaceous cyst. Find out more about what epidermoid cysts look like, whether they cause health problems, and how they are treated, below.

What They Look Like

An epidermoid cyst has a cyst wall that is made of skin cells that are found in the epidermis, the outermost layer of the skin. This cyst wall is like a balloon that projects down into the second layer of the skin, the dermis. This balloon, or cyst wall, makes keratin—a protein that's found in skin, hair, and nails and is white, cheesy, or firm.

A typical epidermoid cyst looks like a raised, round bump. If you touch it, you can typically feel the cyst wall and move the cyst around under the skin fairly easily. Often there is a small opening on the surface of the skin that may look like a scab, but that opening may be so small that it's difficult to see.

What Happens If They Rupture

Epidermoid cysts usually don't cause problems unless they get very large or the cyst wall ruptures, exposing the inside keratin to the surrounding tissue. This is a problem because the contents of an epidermoid cyst are very irritating to the tissue around the cyst.

A ruptured cyst can get red, swollen, and painful. If this happens, it's best to see your doctor.

Sometimes an inflamed cyst needs to be opened to let it drain; if so, your doctor may recommend treating it with warm compresses for a few days to help the cyst continue to drain. Other times, in lieu of opening the cyst, treatment may involve antibiotics or an injection with a corticosteroid (usually triamcinolone).

When to Have Epidermoid Cysts Removed

An epidermoid cyst doesn't have to be removed if it's small, doesn't hurt, and hasn't gotten red and swollen. Doctors typically recommend the removal of a cyst to patients for the following reasons:

  • It's in a place where it gets irritated, rubbing against clothing or jewelry.
  • It's located in a place that is visible and it's getting larger quickly.
  • It frequently gets inflamed or infected.

How They Are Removed

If an epidermoid cyst needs to be removed, it's important that the whole cyst wall is taken out. Remember, it's the cyst wall that makes the keratin contents. If the cyst is merely opened and its contents are drained, the cyst wall remains inside the skin and will start making more keratin, causing the cyst to "return."

An epidermoid cyst is usually removed by making an incision over the cyst and removing most of its contents. Then, the whole cyst wall is separated from the surrounding tissue and removed. If the incision is large enough, it may need to be sutured closed.

Source:

Stone, Mary Seabury. "Cysts." Dermatology. 2nd. Ed. Jean Bolognia. New York: Mosby, 2008: 1681-83.

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