Association between plaque-type psoriasis and perianal streptococcal cellulitis and review of the literature.

Perianal streptococcal dermatitis is an uncommon superficial cutaneous infection of the perianal area almost exclusively described in children. Perianal streptococcal dermatitis is caused by group A beta-hemolytic streptococci and occurs mainly in children between six months and ten years of age. Prior therapy with topical antifungal agents, topical corticosteroids, and oral preparations for pinworms either fails to improve or worsens patient's symptoms. Early antibiotic therapy causes a dramatic and rapid improvement of symptoms. Treatment protocol consists of amoxicillin 40 mg/kg/day, divided into three doses, and/or topical application of mupirocin 2% ointment three times per day for ten days. We describe a four-year-old boy with perianal streptococcal dermatitis who was brought to our clinic with plaque type psoriasis.