They are common skin lesions usually seen as bumps on the surface of the skin. They are sac like structures and this sac is present around the contents of the skin and forms like a capsule which is known as the cyst wall. They are present in both males and females and are seen in approximately one in five of the population. They are harmless and generally asymptomatic but sometimes become inflamed and infected when they are very uncomfortable and may discharge and spontaneously resolve with scarring.

There are several types of  and the most commonly the word cyst in skin is used for an Epidermoid cyst . These are due to overgrowth of epidermal cells, which is the top thinner layer of the skin. They can be one or multiple. They can appear on the trunk face and neck and anywhere on the skin. The cysts appearing on the scalp are known as Pilar cysts. Other types of cysts seen are vellus cysts, trichilemmal cyst (Pilar cyst), dermoid cyst, inclusion cyst.

They are usually removed if they are symptomatic or a source of annoyance as a Pilar cyst on the scalp being caught with a hair brush.

For more information click here