From October 1985 through June 1986, 31 children in a single pediatric practice were treated for perianal signs and symptoms associated with growth of group A beta-hemolytic streptococci from perianal cultures. Signs and symptoms included perianal dermatitis (90%), perianal itching (78%), rectal pain (52%), and blood-streaked stools (35%). Ages ranged from 7 months to 8 years mean 4.25 +/- 1.8 years). There were 24 boys (77%) and seven girls (23%). The 31 cases occurred in 19 families. Intrafamily spread was only to siblings and occurred in 50% of the possible situations. Direct perianal antigen studies had a sensitivity of 89% for predicting positive cultures. Four different T types of group A streptococci were isolated from these cases, but the T type within each family outbreak was identical except in one case. When group A streptococci were found in the pharynx (64% of patients), the T type of the pharyngeal and perianal isolates were identical. Treatment was usually with oral penicillin. Relapses occurred in 39%. Signs of cellulitis were absent in all 31 cases and, therefore, we suggest that the nomenclature for this entity be changed from streptococcal perianal cellulitis to streptococcal perianal disease.