Perianal Group A Strep is an infectious dermatitis seen in the perianal region that is caused by Group A beta-hemolytic Strep. Children will have a characteristic rash with a sharply-demarcated area of redness, swelling, and irritation around the perianal region. There may be associated swelling and irritation of the vulva and vagina (in girls) and penis in boys. Patients can have bleeding or itching during bowel movements.
The age range is often <10 years of age. There is often an absence of fever or other systemic symptoms.The diagnosis can be confirmed by obtaining a Rapid Strep swab from the area of interest. You can also collect a bacterial culture of the area.
Treatment requires a 14 day course of penicillin. Amoxicillin (40 mg/kg/day divided TID) and clarithromycin are alternative treatments. The additional of topical bactroban (mupirocin) can be effective, but it should not be used as monotherapy. Re-occurrence is common, so close follow-up is key.
References
Brilliant, LC. Perianal streptococcal dermatitis. Am Fam Physician. 2000 Jan 15;61(2):391-3, 397.
