Sebaceous cysts are typically harmless, slow-growing bumps under the skin. They often appear on the scalp, face, ears, trunk, back, or groin area. They are sometimes called epidermal inclusion cysts. But it’s more accurate to call them sebaceous cysts.
These cysts can occur because of:
A ruptured follicle linked to acne
A sebaceous duct that doesn't grow correctly
Injury to the area
Sometimes they happen for no clear reason. The cysts usually contain keratin, lipid, and other skin particles.
Cysts can remain stable or they may steadily grow. Sometimes they will become inflamed or suddenly break open (rupture). This poses a risk for infection.
Sebaceous cysts may resolve on their own. But they often come back. Most cysts don’t cause problems or need treatment. But if a cyst is bothering you for any reason, see your healthcare provider.
A cyst can be injected with steroids. This can reduce inflammation and the cyst may not need to be drained. But infected cysts may need to be cut and drained. To do this, your provider makes a hole in (punctures) the top and removes the contents. Large cysts can come back after this procedure and may have to be surgically removed (excised).
If a cyst becomes swollen, tender, large, or infected, treatment may include antibiotics and then surgery.