Sebaceous Cyst

A harmless swelling under the skin that may become infected

  • More common in adults
  • Gender, genetics, and lifestyle are not significant factors

A sebaceous cyst, also called an epidermoid cyst, is a smooth lump that forms under the skin due to inflammation of a hair follicle. The sac is filled with dead skin cells and sebum, the oily secretion of the sebaceous glands. Some cysts have a dark central pore.

Sebaceous cysts commonly occur on the scalp, face, trunk, and genitals but may appear on any part of the body. Although harmless, the cysts occasionally grow large and become unsightly. A sebaceous cyst that is infected by bacteria may become inflamed and painful and eventually burst.

If a sebaceous cyst is not causing you any problems, it can safely be left untreated. However, if the cyst becomes very large or painful, it can be removed under a local anaesthetic. The cyst will usually be taken out intact because it can recur if the sac and its contents have not been completely removed. If it becomes infected, antibiotics or incision and drainage may be required.

Sebaceous cyst on the scalp

The scalp is a typical site for a sebaceous cyst, which is a smooth, harmless lump that develops under the skin.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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