What's in this article?
Epidermoid cysts, also called sebaceous, keratin, or epithelial cysts, are small, hard lumps that develop under the skin. These cysts are common. They grow slowly. They do not cause other symptoms and are not cancerous. Epidermoid cysts are often found on the face, head, neck, back, or genitals.
An epidermoid, or epidermal, cyst is a small, movable lump under the skin. It forms when surface skin cells move deeper into the skin and multiply. These cells form the wall of the cyst and secrete a soft, yellowish substance called keratin, which fills the cyst. If the wall of the cyst is ruptured, the keratin is discharged into the surrounding skin, which causes irritation and inflammation.
The cyst may remain small for years, or it may continue to get larger. These cysts are rare in children but common in adults. Cysts are not cancerous.
What Causes Epidermoid Cysts?
Epidermoid cysts are usually caused by a buildup of keratin. Keratin is 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. The blockage causes keratin to accumulate, causing the bump or cyst to develop.
An epidermoid cyst is more likely to develop in people with acne or other skin conditions.
Symptoms of Epidermoid Cysts
Epidermoid cyst signs and symptoms include:
- 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
Your doctor can examine the swelling and tell you if you have a cyst.
A cyst may disappear on its own or remain indefinitely.
There is no way to prevent epidermoid cysts.
What Is the Prognosis for Epidermoid Cysts?
In most cases, epidermoid cysts cause no long-term problems. Squeezing out the contents of the cyst can lead to infection, so it’s best to leave the cyst alone.
Once a cyst is drained, there is a possibility that it will grow back. Very rarely, epidermoid cysts can become cancerous.
How Are Epidermoid Cysts Treated?
Most epidermoid cysts either stop growing and stay as-is or go away on their own without treatment. Physicians will usually make note of a cyst and monitor it during each checkup to make sure that it has not changed. Since epidermoid cysts are very rarely cancerous, they do not pose a risk. Most are never treated.
Treatment may be required if the cyst becomes red, swollen, and painful or is infected. In such cases, treatment options include antibiotics and steroid injections. In rare cases, the cyst may be surgically removed, or cut and drained. The cyst can also be removed for cosmetic reasons.
Treatments and drugs
You can usually leave a cyst alone if it doesn’t cause discomfort or cosmetic problems. If you seek treatment, talk with your doctor about these options:
- Injection. This treatment involves injecting the cyst with a medicine that reduces swelling and inflammation.
- Incision and drainage. With this method, your doctor makes a small cut in the cyst and gently squeezes out the contents. This is a fairly quick and easy method, but cysts often recur after this treatment.
- Minor surgery. Your doctor can remove the entire cyst. You may need to return to the doctor’s office to have stitches removed. Minor surgery is safe and effective and usually prevents cysts from recurring.
If your cyst is inflamed, your doctor may delay the surgery.
- Lasers. This method involves using a carbon dioxide laser to vaporize the cyst. It results in minimal scarring.