Painful skin cyst: what to know

A cyst is a sac beneath the skin that can become tender when inflamed or infected. A boil or abscess may also form a painful, warm lump with pus. Cellulitis usually causes spreading redness and warmth rather than one well-defined sac. Recurrent painful lumps in skin folds may fit hidradenitis suppurativa, while a band of pain and blisters can suggest shingles. A clinician may examine the surface, depth, drainage, and surrounding skin before choosing care.

Keep the area clean, avoid squeezing or piercing it, and reduce pressure from clothing or straps. A warm, clean compress may ease tenderness for some superficial lumps; stop if discomfort increases. Cover an area that is draining with a clean dressing and wash hands after touching it. Do not use someone else’s antibiotics or apply strong creams to an unexplained lump. Assessment is useful when the lump is painful, enlarging, recurrent, or not settling.

Seek prompt medical care if redness spreads, the area becomes hot, pus collects, pain escalates, or you develop fever or feel unwell. Urgent review is needed for a lump near the eye, nose, or genitals, a rapidly enlarging swelling, red streaks, or difficulty moving the nearby joint. Emergency help is appropriate for confusion, faintness, or breathing difficulty.

Ask whether the lump is a cyst, boil, abscess, cellulitis, shingles, or another problem; whether drainage is appropriate; whether a sample is needed; and how to care for the wound or prevent repeated episodes.