What are the causes of bleeding in anal fistula?
Nov 15, 2025
Source: Cainiu Health
Dr. Li Jingxiang
Introduction
Bleeding from an anal fistula may be caused by bowel movement irritation, local friction, fistula infection, perianal abscess, or perianal eczema. It can be improved by adjusting bowel movements, reducing irritation, and medication. If bleeding increases or is accompanied by severe pain, prompt medical attention is necessary. Hard, dry stool passing through the area of the anal fistula can cause friction against the fistula's mucosal lining, leading to tissue damage and bleeding.
Rectal fistula bleeding may be caused by defecation irritation, local friction, anal fistula infection, perianal abscess, or perianal eczema. Symptoms can be improved through adjustments in bowel habits, reducing irritation, and medication. If bleeding increases or is accompanied by severe pain, prompt medical attention is necessary.
1. Defecation irritation: Hard, dry stools passing through the fistula site can cause mucosal abrasion and minor bleeding due to friction. Bleeding is usually slight and occurs after bowel movements. It is recommended to drink more water, consume more dietary fiber, maintain smooth bowel movements, and avoid straining during defecation to reduce mucosal irritation.
2. Local friction: Prolonged sitting or wearing tight clothing can lead to continuous friction on the fistula area, causing mucosal congestion, damage, and bleeding, often accompanied by local discomfort. It is advised to avoid prolonged sitting or standing, and wear loose, breathable cotton clothing to reduce local pressure and friction.
3. Anal fistula infection: Bacterial growth within the fistula tract can trigger inflammation, leading to mucosal congestion, erosion, and bleeding, often accompanied by pus discharge and odor. Under medical guidance, medications such as cefixime dispersible tablets, metronidazole suppositories, and potassium permanganate solution may be used to alleviate symptoms.
4. Perianal abscess: A perianal abscess may rupture and develop into an anal fistula. When the abscess recurs, inflammatory infiltration can affect blood vessels, resulting in bleeding along with redness, swelling, and increased pain around the anus. Under medical supervision, medications such as levofloxacin capsules, cefuroxime axetil tablets, and compound alginates suppositories may help improve symptoms.
5. Perianal eczema: Recurrent perianal eczema can irritate the skin surrounding the fistula, causing skin breakdown and bleeding, accompanied by intense itching and rashes. Follow medical advice to use desonide cream, erythromycin ointment, loratadine tablets, and other medications to relieve symptoms.
Maintain perianal hygiene by washing with warm water and drying thoroughly afterward. Eat a light diet, avoiding spicy and greasy foods. Maintain regular sleep patterns and avoid staying up late. Engage in moderate exercise to strengthen the immune system and support symptom relief and recovery.
