What should you know about a dark cyst under the skin?

An epidermoid-type cyst can form when skin cells collect beneath the surface. It may be skin-coloured, darker, or inflamed, and it can feel round and mobile. An abscess is more likely to be hot, increasingly painful, red, and filled with pus. Bruising, a blocked follicle, or pigment left after inflammation can also look dark. A general guide to a new lump is available under [Skin Lumps](/symptoms/skin-lumps/).

A clinician may check whether the lump is superficial or deep, whether it moves, and whether there is drainage or spreading inflammation. Do not assume that every dark lump is a cyst.

Avoid squeezing, cutting, or inserting a needle into the area. Keep it clean, protect it from rubbing, and use a warm compress if it is tender. Take a clear photograph and note changes in size, pain, warmth, and discharge. If it persists, returns, or interferes with movement, book a skin assessment.

Treatment depends on the finding. A clinician may discuss an [Intralesional Steroid Injection](/treatments/injectables/intralesional-steroid-injection/) for selected inflammation, [Abscess Drainage](/treatments/minor-procedures/abscess-drainage/) when a collection of pus needs release, or [Cyst Removal](/treatments/surgical-dermatology/cyst-removal/) when a cyst repeatedly causes problems.

Seek prompt care for spreading redness, increasing warmth, severe tenderness, pus, fever, chills, or feeling unwell. Arrange a routine review if the lump remains, becomes hard or fixed, bleeds, opens repeatedly, or changes in colour or shape. Rapid swelling or severe pain warrants urgent assessment, particularly if the area limits walking or normal activity.

Ask what the lump most resembles and whether it needs imaging, drainage, injection, or removal. Ask how to protect the area while it heals, how to recognise recurrence, and whether any medication or health condition could affect treatment or healing.