Rash on the buttocks

Sitting, exercise, tight clothing, and dampness can irritate the skin or inflame hair follicles, especially when bumps are centred around hairs. Moisture in the cleft or skin folds can contribute to intertrigo. A sharply scaly or ring-shaped patch can suggest ringworm. Atopic dermatitis, contact dermatitis, psoriasis, and heat rash can also affect this area. New medicine can produce a more widespread drug rash. Painful lumps, drainage, or a tender swelling near the cleft need direct examination.

Wash gently, pat dry, change out of sweaty clothing, and choose breathable underwear and looser trousers. Stop new fragranced wipes, creams, detergents, or topical medicines until the trigger is clearer. Avoid squeezing bumps and do not share towels. A clinician may need to inspect the rash or take a sample before selecting an antifungal, anti-inflammatory, or antibacterial treatment.

Seek prompt care for rapidly worsening redness, spreading warmth, pus, severe pain, fever, a deep tender lump, or difficulty sitting. Urgent help is needed for facial swelling, breathing difficulty, blistering, or skin peeling. Make an appointment if the rash persists, recurs, forms a ring, or does not improve with gentle skin care.

Are the bumps centred on follicles or located in a skin fold? Could moisture, friction, fungus, or contact irritation be involved? Should I use a particular cleanser? Would a swab or scraping clarify the diagnosis?