Group A beta-hemolytic Streptococcus: an exceptional etiology for perianaldermatitis in adults?

Background Perianal dermatitis usually occurs in children between 1 and 8 y ears of age. We report a sixth case in an adult. Case report. A 33 year-old woman complained of perianal itching which quick ly extended to the vulva and persisted in spite of anti-hemorrhoid and anti -fungal treatments. After 12 days, she had painful defecation, a well demar cated perianal and vulvar erythema and anal collection. Culture from a peri anal swab isolated group A beta-hemolytic Streptococcus (ABHS). After surgi cal treatment of the collection and a 7 days oral amoxicillin regimen, the patient recovered with no recurrence. Discussion. Symptoms of perianal dermatitis are unspecific, leading to dela yed diagnosis and underestimated frequency. Symptoms consist in perianal er ythema. Swab culture shows ABHS. The mechanism of colonization of perianal area is not well defined. Although treatment Kith oral penicillin is usuall y effective, failures and relapses have also been reported. Complications s uch as deep infection or abcess formation are infrequent. A bacterial swab should be mode in patients with persisting perianal erythma.