An anal fistula is an abnormal tunnel or connection that forms between the inside of the anal canal and the skin near the anus. It is often caused by an infection in an anal gland that forms an abscess, which can then create a tunnel to the surface as it tries to drain. Fistulas can cause discomfort, pain, and recurrent infections, and they generally require medical treatment to heal.

Causes of Anal Fistula

• Abscess Formation: Most fistulas are the result of an anal abscess that didn’t completely heal or was inadequately drained.
• Inflammatory Bowel Disease: Conditions like Crohn’s disease increase the risk of fistula formation due to chronic inflammation.
• Infections: Tuberculosis, sexually transmitted infections, and other infections can lead to fistulas.
• Trauma or Surgery: Injury or surgical procedures in the anal area can occasionally lead to fistula formation.

Symptoms of Anal Fistula

• Pain and Swelling Around the Anus: Especially during bowel movements or when sitting.
• Discharge of Pus or Blood: This may be persistent or intermittent, often accompanied by a foul odor.
• Skin Irritation: Due to persistent drainage, causing itching or soreness around the anus.
• Recurrent Abscesses: A cycle of abscess formation and drainage can be a sign of an underlying fistula.
• Fever and Fatigue: In cases of infection or recurring abscesses.

Diagnosis of Anal Fistula

• Physical Examination: A doctor may detect the fistula by inspecting the area around the anus.
• Proctoscopy or Sigmoidoscopy: To examine the anal canal and rectum and identify the fistula’s internal opening.
• Imaging Tests: MRI or ultrasound may be used to get a detailed view of the fistula’s pathway, especially if it is complex or deep.