A 27-year-old man will have a scar on his face for the rest of his life, after what he thought was a pimple turned out to be an infected cyst. In late 2024, Kai Davidson noticed a small lump on ...

Pilonidal sinus is a skin infection that causes a cyst near the buttocks, just beneath the tailbone. The infection often occurs when an ingrown hair grows internally and infects the skin.

It may resemble a pit or small depression in the skin. According to the Pilonidal Support Alliance, 99% of the cysts are abscesses, which are pockets of infection underneath the skin.

For cysts, you only need antibiotics if there's an infection. A direct injection of diluted corticosteroid (often prednisone) into the cyst is an option if there's swelling.

A Bartholin abscess is an infected and inflamed cyst that develops when a Bartholin’s gland becomes blocked and infected. This forms a painful, swollen lump filled with pus near the vaginal opening.

The cyst can also become infected and form an abscess, or a painful, puss-filled pocket. Once branchial cysts begin growing, doctors will advise immediate removal to prevent further infection.