=anal pain.

Rule out anal fissure (may be hard to see but bleeding or sentinel pile are clues, typically caused by constipation), thrombosed haemorrhoid, infection.

After that, functional (see Rome criteria)- often triggered by defaecation or sitting.

Classifed as acute (less than 20 mins – “fugax”) or chronic (greater than 20 mins episodes). Latter thought to be due to paradoxical pelvic floor contraction.

Biofeedback has best evidence but consider tricyclic antidepressants, Botox, and sacral nerve stimulation (!).