A nine-month-old male presented with intense perianal erythema.
A first rectal smear was performed and the result of the rapid antigen detection test negative for Streptococcus at 24 hours was negative. Treatment with clotrimazole was initiated.
Since the patient did not evolve well, it was decided to repeat the rectal swab and pharyngeal mask, finding a positive result for rapid detection of streptococcus antigen in the rectal swab and negative in the pharynx.
The rectal swab culture was negative for GAABHS growth.
Treatment was initiated with oral penicillin for ten days, with resolution of the symptoms.
