Hard lump on buttocks under the skin: what to know

Pressure, sweating, friction, an ingrown hair, a cyst, or an inflamed follicle can produce a buttock nodule. A boil is often sore and warm, with increasing redness or drainage. A lump near the cleft may be affected by local pits or repeated irritation, whereas a bump elsewhere may have a different origin. A firm mass can also be scar tissue or another growth. The appearance and feel cannot reliably identify the cause without an examination.

Keep the skin gently clean, dry it carefully, and reduce prolonged pressure with movement or a cushion. Choose breathable clothing and avoid picking, squeezing, or trying to open the lump. If it is draining, use a clean dressing and wash your hands after touching it. Make an appointment if the bump lasts, returns in the same place, grows, or makes sitting difficult. [Skin Lumps](/symptoms/skin-lumps/) provides broader information about this symptom.

Seek urgent care for severe pain, rapidly spreading redness, fever, chills, marked swelling, foul drainage, or feeling significantly unwell. Prompt assessment is needed for a fixed or enlarging lump, bleeding, an open sore, or skin that changes around it. [Boils](/conditions/boils/) may need professional treatment when infection is worsening. A persistent unusual skin lesion may prompt consideration of [Basal Cell Carcinoma](/conditions/basal-cell-carcinoma/), but that possibility cannot be inferred from a lump alone.

Ask whether pressure, hair follicles, a cyst, or a deeper process best fits the finding. Ask how to protect the area while sitting, whether drainage needs treatment, and which changes require a rapid return. If inflammation or a scar is suspected, ask whether [Steroid Injection Into The Skin](/treatments/injectables/intralesional-steroid-injection/) could help and what its risks are.