A fistula-in-ano is an abnormal tunnel that forms between the inside of the anal canal and the skin around the anus. It usually develops following an infection or abscess near the anus, when a small passage remains after the abscess drains. Common symptoms include persistent pain or discomfort around the anus, swelling, redness, and repeated discharge of pus or blood from a small opening near the anus. The discharge may be associated with an unpleasant smell, and the opening may close and reopen repeatedly. A fistula usually does not heal completely on its own and requires medical evaluation for appropriate treatment.
Treatment of an anal fistula usually involves surgery, with the type of procedure depending on the location and complexity of the fistula and its relationship to the anal sphincter muscles. Procedures may include fistulotomy, placement of a seton, or other sphincter-preserving techniques. After treatment, the patient should keep the area clean, take prescribed medications, eat a fibre-rich diet, drink adequate water, and avoid straining during bowel movements. Warm sitz baths may help relieve discomfort and maintain cleanliness. Follow-up visits are important to monitor healing and detect recurrence. The patient should seek prompt medical attention if they develop fever, increasing pain or swelling, heavy bleeding, or worsening pus discharge.