Understanding Epidermoid Cyst

Side view of woman's head showing epidermoid cyst. Inset shows cross section of epidermoid cyst.

An epidermoid cyst is a small abnormal growth in the top layers of the skin. It is filled with keratin, the same proteins that make up your hair and nails. These cysts grow slowly. They can grow anywhere on the body. But they are most often found on the face, behind the ears, and on the chest or upper back.

How to say it

ep-ih-DUHR-moid sist

What causes an epidermoid cyst?

An epidermoid cyst may occur because of an injury to the skin or from acne.

Symptoms of an epidermoid cyst

An epidermoid cyst is a subcutaneous bump. This means it is just below the skin. It may be yellow or skin-colored. It often has a small black mark in the middle of it, like a blackhead.

An epidermoid cyst rarely causes pain, unless it ruptures or becomes infected. It may ooze keratin, a white, cheesy, smelly material. If the cyst becomes inflamed or infected, it may be:

  • Bad smelling

  • Red

  • Swollen

  • Tender

Treatment for an epidermoid cyst

Many epidermoid cysts don’t cause any problems. They don’t necessarily need to be treated. They may go away on their own. But you may want to treat it if you don’t like how it looks or it becomes inflamed.  Treatment options include:

  • Steroid injection. A steroid may be injected into the cyst. This may help ease inflammation. It may also prevent infection.

  • Surgical removal. The cyst can be cut out. It may also need to be drained first. There is a slight chance the cyst may come back.

  • Antibiotics. In some cases, you may need to take an oral antibiotic to prevent infection and regrowth.

When to call your healthcare provider

Call your healthcare provider right away if you have any of these:

  • Fever of 100.4°F (38°C) or higher, or as directed

  • Redness, swelling, or fluid leaking from your incision that gets worse

  • Pain that gets worse

  • Symptoms that don’t get better, or get worse

  • New symptoms