Anorectal Abscess (Perianal Abscess, Ischiorectal Abscess, Anal Abscess)

An abscess is a collection of pus (white blood cells). Abscesses are painful because the pus is under some pressure. The most common cause of abscesses in the anorectal area are infected anal fissures, and infected anal glands. We have anal glands just as dogs and skunks have anal glands. Ours are not very well-developed. An infection within an anal gland can lead to an abscess. Anal glands may become infected after a bout of diarrhea, but often we don’t know why it happens.

Abscesses in the anorectal area are usually small (perianal abscess – a cm or two), but they can occasionally be very large (ischiorectal abscess – the size of a large grapefruit). Abscesses can vary in significance from a minor problem to a life-threatening issue. Very small abscesses may be managed with antibiotics alone, but most will require an incision or needle to drain the pus out, often done as an emergency procedure to stabilize a patient who is ill or in a lot of pain. Definitive surgery to fix the underlying problem will often be required at a later date when the patient is well.

Michael E Pezim, MD FRCSC FACS
Pezim Clinic, Vancouver, British Columbia, Canada