A 30 month old girl had a painful itchy red rash around the anus that failed to improve with topical antifungal therapy for 1 month. The perianal erythema had well-defined margins and there was a thin mucoid exudate. A perianal skin culture was positive for Group A beta-hemolytic streptococcus, and the eruption and symptoms cleared when she was treated with penecillin V, 75OOO U/kg/day for 21 days. Perianal streptococcal dermatitis can masquerade as candidiasis, psoriasis, seborrheic dermatitis, inflammatory bowel disease or sexual abuse. Perirectal tenderness and pain during defecation can result in constipation, particularly when the diagtnosis is not considered and effective therapy is delayed for months. Complications related to streptococcal infections (nephritis, rheumatic fever, guttate psoriasis) can coexist. Streptococci can be found in the pharynx, too.
Bright red well demarcated perianal patch with erosion