Perianal streptococcal dermatitis is a superficial infection of the perianal skin, most often caused by group A beta-hemolytic streptococci (GABHS) that typically affects young children.

Clinical findings vary from a very subtle eruption that is overlooked to a well-demarcated area of bright pink to red erythema that extends 2 to 3 cm from anus (Fig. 5.9).

Typically presents as a sharply demarcated, bright red erythema with a moist, tender surface.

Occasionally the surface can be moist with an overlying pseudomembrane.

Can also present with dry pink scaly plaque.

Infrequently accompanied by itching, fissuring, pain, and mucoid discharge.

May become more of a cellulitis, with possible pain on defecation.

Fever is usually absent but sometimes patients also have streptococcal pharyngitis.

Bacterial culture of the perianal skin can confirm the diagnosis.