Infantile perianal protrusion: 13 new cases.

We report 13 girls, ages 4 months-5 years, affected by an infantile perianal protrusion located on the midline anterior to the anus in 8 patients and posteriorly in 3. A past personal history of constipation existed in six patients and anal fissures in three patients. In one of the five patients with recurrent anogenital erythema, a punch biopsy specimen revealed the histopathologic signs of lichen sclerosus et atrophicus (LS&A). In another two patients, infantile perianal protrusion was associated with clinical signs of genital LS&A. None of our patients had spontaneous reduction of infantile perianal protrusion during the follow-up period.