• Five case reports of perianal cellulitis caused by group A β-hemolytic streptococci are presented. These reports illustrate delays in diagnosis and therapy of this condition that may present as chronic diaper dermatitis, perirectal fissures, painful defecation, fecal hoarding behavior, or protocolitis. One patient had associated guttate psoriasis. In children especially, guttate psoriasis should alert physicians to culture perirectal as well as pharyngeal sites for group A streptococci. (Arch Dermatol 1988;124:702-704)