PERIANAL dermatitis of the newborn is a common eruption which is not described in leading American dermatologic and pediatric textbooks.1 This may be because of confusion with the well-recognized napkin dermatitis. The two differ, however, in location, age incidence, and cause.
Napkin dermatitis is also called diaper eruption, erythema gluteale, and erythema of Jacquet. This, in the words of Cooke,2 is a dermatitis "limited to the convex surfaces of the thighs and buttocks since the approximated flexures and the sulci between them are protected from constant contact with the diaper and ammonia." The perianal dermatitis, on the other hand, is an irritation of the skin about the anus. It is erythematous, red, and frequently exudative. Patients with severer disease show multiple small superficial ulcerations. The involved area varies from 3 to 4 cm. in diameter and centers at the anus. The inflammatory reaction fades gradually at the periphery.
PRATT AG. PERIANAL DERMATITIS OF THE NEWBORN. AMA Am J Dis Child. 1951;82(4):429-432. doi:10.1001/archpedi.1951.02040040447003