What should you know about lump in bum crack under skin?

The cleft is exposed to friction, sweat, pressure, and moisture. A blocked hair follicle or local infection can produce a tender lump; surrounding skin may crack, itch, or sting. Dry, inflamed skin can also split, and conditions such as [Atopic Dermatitis](/conditions/atopic-dermatitis/) or [Psoriasis](/conditions/psoriasis/) may affect folds and the skin around them. These conditions can present with cracking, but a lump should not automatically be attributed to a rash.

The exact location matters. A lump beside the cleft, close to the anus, or higher over the tailbone can have different causes and may need different treatment.

Wash gently, pat dry, and choose loose breathable clothing. Avoid scrubbing, fragranced products, shaving over the area, and squeezing or puncturing the lump. A bland moisturiser may protect dry surrounding skin; [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/) explains this approach. Do not place cream into an open wound or use steroid, antibiotic, or antifungal products without advice.

Record changes in tenderness, size, drainage, skin cracking, and bowel-related discomfort. Book an examination if the lump does not settle, repeatedly returns, or makes sitting or walking difficult.

Seek prompt care for severe or worsening pain, a rapidly expanding swelling, pus, fever, spreading redness, or difficulty sitting. Get urgent help for heavy bleeding, severe illness, or loss of bowel control. A persistent open area or recurrent crack can be reviewed under [Cracked Skin](/symptoms/skin-cracking/).

Ask whether the lump is in the skin, a hair-bearing area, or near the anus; whether there is infection or a chronic inflammatory condition; and which cleanser, barrier, or prescription treatment is appropriate.