[Perianal abcess in infant].

Introduction: Perianal abcess and fistula-in-ano are particular when happening in infants of less than 1 year of age. A congenital abnormality of crypts of Morgagni may be at the origin of the disease. There is no evidence for predisposing condition at this age.
Case Report: A 7-week-old boy had a painful swollen perianal lesion suggesting the presence of perianal abcess. Biological tests did not show any neutropenia nor inflammatory syndrome. The infant was admitted to the surgical center to undergo a perianal abcess drainage. During the intervention, no fistula was found. No recurrence was observed.
Discussion: Perianal abcess and/or fistula-in-ano are relatively common conditions in infants of less than 1 year of age. This disease is suspected to originate from anal cryptitis, which will later form a perianal abcess. Androgen excess during the foetal stage could be the cause of the formation of abnormal crypts of Morgagni, which encourages cryptitis and abcess formation. In childhood some predisposing factors can exist, as immunodeficiency or colopathy. On the opposite, a predisposing condition is rare in infancy. Twenty-eight to 85 per cent of infants with perianal abcess may progress to form a fistula. The usual treatment of perianal abcess is incision and drainage; it may be completed by fistulotomy or fistulectomy. The antibiotherapy is not systematic. The identification of the corresponding crypt may be important to avoid recurrence. On the opposite, a recent prospective study proposes a non operative management of perianal abcess and fistula-in-ano in healthy infants.