Guttate psoriasis triggered by perianal streptococcal infection.

The association of guttate psoriasis (GP) with streptococcal pharyngitis is well accepted. However, less is known about the association with perianal streptococcal infection. We report a case of a 19-month-old boy with GP after a preceding perianal streptococcal dermatitis, with no clinical signs of a streptococcal pharyngitis. Treatment with phenethicillin was given together with mometasone ointment. After 4 weeks, the perianal redness was reduced and the psoriasis had improved significantly. A review of the literature revealed nine previous case reports, comprising a total of 15 patients. In all cases, the perianal dermatitis and the GP improved after treatment with oral antibiotics, sometimes in combination with topical corticosteroids. We conclude that in cases of GP in children, the perianal area must be examined for streptococcal infection.