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Perianal streptococcal dermatitis

Author: Dr Mark Duffill, Hamilton, New Zealand, 2008.

What is perianal streptococcal dermatitis?

Perianal streptococcal dermatitis is an infectious condition of the skin around the anus in children. It is caused by group A beta-haemolytic streptococcus bacteria.

What are the symptoms of perianal streptococcal dermatitis?

Perianal streptococcal dermatitis presents with sharply demarcated redness, local swelling and itch of the area around the anus. It may be accompanied by inflammation of the vulva and vagina in girls (or end of the penis in boys), pain on passing a bowel motion, constipation, cracks in the anus and discharge of pus and/or blood from the rectum.

What is the cause of perianal streptococcal dermatitis

Perianal streptococcal dermatitis is caused by streptococcal bacteria of the group A beta-hemolytic type.

The same bacterium may be carried in the throat. The bacteria may be passed to other children. However, some children carry the bacteria in the anal and genital area without it causing disease.


A swab for bacterial culture will confirm the diagnosis. A rapid streptococcal test may provide a quicker result.


Oral penicillin for 14 days is usually prescribed. Amoxicillin and clarithromycin are alternatives. A repeat course of antibiotics is sometimes required.

The condition may recur, in which case the treatment may be repeated.

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