Anal fissures, abscesses and fistulas are related conditions occurring near or in the anus that produce similar symptoms. An abscess is an infected cavity filled with pus that’s found near the anus or rectum. Most abscesses result from blocked anal glands. An anal fistula can occur in about half of people who develop an anal abscess. A fistula is a tunnel that forms under the skin connecting the infected glands to the abscess. Painful bowel movements, bleeding, swelling, skin irritation and a fever are common abscess and fistula symptoms.
An anal fissure is a tear in the tissue lining the anus. Fissures can occur from passing large or hard stools and cause pain and bleeding with bowel movements. They are common in infants but can affect people at any age.