Perianal Disease: Fissure, Abscess, and Fistula

Key Points Anal fissure is a tear in the mucosa of the anal canal between the anocutaneous junction and the dentate line. Fissures may manifest with bright red blood or pain with stooling.Uncomplicated fissures can typically be managed conservatively by treating constipation with laxatives and managing painful symptoms as the fissure heals.Perianal abscess is an infection located in the subcutaneous space adjacent to the anus and below the sphincter complex.Perianal fistula is an abnormal fistulous connection between the anal canal or rectal mucosa and the skin, which may form after a perianal abscess. Fistulae in infants are typically superficial and do not involve the sphincter muscle.First-line treatment of perianal abscess and perianal fistula in infants younger than 12 months is conservative management, as both conditions have high rates of resolution without surgery.Workup for Crohn disease should be considered in either older children and adolescents or patients with complex or recurrent abscesses, fistulae, or fissures despite optimal management.