Perianal streptococcal dermatitis.

Perianal streptococcal dermatitis is a bright red, sharply demarcated rash that is caused by group A beta-hemolytic streptococci. Symptoms include perianal rash, itching and rectal pain; blood-streaked stools may also be seen in one third of patients. It primarily occurs in children between six months and 10 years of age and is often misdiagnosed and treated inappropriately. A rapid streptococcal test of suspicious areas can confirm the diagnosis. Routine skin culture is an alternative diagnostic aid. Treatment with amoxicillin or penicillin is effective. Follow-up is necessary, because recurrences are common.