“I’ve got a really painful swelling at the top of my bum cleft that’s started leaking — I can’t sit down”

PILONIDAL DISEASE is a sinus/cyst in the midline NATAL CLEFT (top of the buttock crease), typically with one or more midline PITS and related to hair/friction, commonest in young, hirsute men and those who sit a lot or are overweight; intermittent discharge/pits with a now painful, red, fluctuant swelling indicates a PILONIDAL ABSCESS. Distinguish the ACUTE ABSCESS (painful, red, hot, fluctuant, may discharge pus) from a chronic/quiescent sinus — the abscess is the urgent issue. An acute pilonidal abscess needs INCISION AND DRAINAGE, usually through an off-midline incision with definitive surgery deferred (European Society of Coloproctology 2024, international): arrange same-day surgical assessment (drainage in primary care only if competent, equipped and the abscess is suitable) with analgesia (paracetamol and, if suitable, ibuprofen at BNF doses), after checking observations face to face (NICE NG253 if systemically unwell) and asking about diabetes or immunosuppression, recognising that ANTIBIOTICS are NOT a substitute for drainage and should be reserved for surrounding cellulitis or systemic features (NICE NG141) — an undrained abscess will not settle on antibiotics alone. For the underlying SINUS (the recurrent problem), refer to general/colorectal surgery for definitive management once the acute episode settles (the surgeon chooses minimally invasive or excisional options; recurrence after drainage alone is common, so definitive care matters; asymptomatic pits need no operation). Advise prevention and hygiene — keep the area clean and dry, and hair removal around the cleft is widely advised though the evidence is limited, with weight discussed sensitively — and consider the differential (perianal abscess/fistula closer to the anus, hidradenitis suppurativa with other flexures, infected sebaceous cyst). Handle a painful, embarrassing problem sensitively, arrange drainage rather than antibiotics alone, refer for definitive treatment, and safety-net for spreading infection/systemic features.