Copy edited by Gus Mitchell. October A perianal dermatosis is a rash or skin change around the anus , between the buttocks.
Patients with a pre-existing inflammatory dermatosis may have anogenital involvement as commonly occurs with psoriasis , or the dermatosis predominantly involves the anogenital area eg, lichen sclerosus.
Patients are often embarrassed, and it may be difficult for them to visualise and examine the area. Their quality of life can be markedly affected yet do not mention it at medical appointments. A compromised skin barrier may predispose to a perianal dermatosis. Advanced age, faecal incontinence, immobility , hyperhidrosis , obesity, occlusion from clothing, and poor anal hygiene all contribute to skin barrier dysfunction.
Because of the effects of occlusion and maceration , scaling may not be apparent, and the skin signs may be non-specific, although there are usually clinical clues to make the diagnosis. It is important to ask about and look for skin problems elsewhere. Perianal dermatoses often present with itch see Itchy anus. Pruritus ani means itch around the anus with no visible skin change when used in the strict sense.
Intertrigo is an inflammatory rash in a skin fold, often due to sweat and friction, an inflammatory dermatosis, or infection. Perianal irritant contact dermatitis can be due to:. Topical allergens that can cause perianal allergic contact dermatitis include:. Flexural psoriasis often involves the anogenital skin and natal cleft , presenting with well- demarcated symmetrical , non- scaly erythema. There will be signs of psoriasis elsewhere such as in other skin folds, scalp , or nails.
