Subcutaneous Cyst on the Back: What to Know

An epidermoid cyst may feel smooth, firm or fluctuant and can have a small opening at the surface. It may remain quiet, become irritated by friction, or become inflamed. A painful, hot, rapidly enlarging lump with redness may instead indicate an abscess or an inflamed cyst. A wider overview of similar findings is available under Skin Lumps.

A clinician may diagnose it by looking and feeling the area. Imaging or a sample may be considered when the lump is unusual, deep, fixed, or difficult to classify.

Do not squeeze, pierce or repeatedly press the lump; this can worsen inflammation and introduce infection. Keep the skin clean, reduce rubbing from clothing or backpack straps, and note changes in size, tenderness, redness or drainage. Treatment depends on the finding: an inflamed lesion may be managed differently from a quiet cyst, while complete Cyst Removal can address the sac when appropriate.

Steroid Injection Into The Skin may be discussed for selected inflammation, but it does not suit every lump. If infection has collected, Abscess Drainage may be needed.

Arrange a medical assessment for a new, persistent, recurrent, enlarging, hard or fixed lump. Seek prompt care for spreading redness, warmth, severe tenderness, pus, fever, or feeling unwell. Urgent assessment is appropriate if swelling is rapidly expanding or pain is severe.

Ask whether the lump appears to be a cyst, whether it is inflamed or infected, whether it should be watched or removed, and what changes should trigger a return visit.