Take 5: Pruritus ani

What investigations are required when a patient presents with irritation around the anal canal?

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What investigations are required when a patient presents with irritation around the anal canal?

“I think everyone gets an itchy bottom from time to time,” says Dr John Lumley, a colorectal surgeon and the director of colorectal diagnostics.

Pruritus ani, which refers to a chronically itchy bottom or an itching, burning sensation around the anal canal, affects around 1-2% of people.

Patients with pruritus ani may have no signs of irritation. However, in those with chronic symptoms, the perianal is often excoriated, thickened, with pale skin and there may be some fissuring present.

“Initially not a lot of investigations are required,” says Dr Lumley.

“If you can find the signs around the bottom of chronic anal fissuring, thickened skin, [do] a simple digital examination to make sure there is no other cause such as a low rectal cancer causing mucous leakage and make sure they don’t have a patulous anus causing leakage.

“And then a simple proctoscopy to look for haemorrhoids is usually all that is required.”

Pruritus is generally caused by mucous leakage on the perianal skin. As mucous is an irritant, it causes chemical dermatitis and a burning itching sensation.

“All you’ve got to do is keep the skin away from the mucous and the mucous away from the skin,” says Dr Lumley.

“So bulking agents such as Metamucil and Benefiber help to bulk and also coat faeces so that the mucous tends to stay on the stool instead of getting on the skin.

“Using baby wipes or some sort of more liquid wash rather than plain old toilet paper to get rid of the mucous helps.

“Having a shower after defecation helps but sometimes it is a bit hard to do that if you’re working.”

[media_embed]https://player.vimeo.com/video/203408237[/media_embed]

In this video, Dr Lumley discusses:

– How common is pruritus ani?
– How does this present?
– What signs can be found on examination?
– What investigations are required?
– How do you treat uncomplicated pruritus ani?