Perianal Abscess Drainage

About Perianal Abscess Drainage

Perianal abscess drainage is a common emergency procedure in colorectal and general surgery. Most perianal abscesses arise from infection of the small anal glands that open into the anal canal, according to the cryptoglandular theory, and they are classified by location as perianal, ischioanal, intersphincteric or supralevator. Typical features include severe constant pain around the anus, swelling and redness, and sometimes fever. Drainage is the definitive treatment: under local or general anesthesia, an incision is made over the abscess close to the anus, the pus is released and the cavity is left to drain, sometimes with a small catheter or packing. Deeper abscesses may need examination under anesthesia and imaging such as MRI or endoanal ultrasound. Antibiotics are not routinely needed for simple abscesses in otherwise healthy people but are used when there is spreading cellulitis, systemic illness, immune suppression or certain other conditions. A substantial proportion of perianal abscesses are followed by an anal fistula, an abnormal tract between the anal canal and the skin, which may require fistulotomy, placement of a draining seton or other repairs. Recurrent or complex abscesses can be associated with Crohn disease. Necrotizing soft tissue infection of the perineum, known as Fournier gangrene, is a rare but life threatening condition that requires urgent extensive surgical debridement. The drained cavity heals gradually from its base.