Anal Fistula: Symptoms, Treatment & When to See a UK Online Doctor

An anal fistula, medically known as a fistula-in-ano, is a small, abnormal track or tunnel that connects the internal lining of the anal canal to the surface of the skin near the anus. This condition often develops following an infection in an anal gland, which results in a collection of pus known as an abscess. While the abscess may drain naturally or be surgically treated, the tunnel created by the pus remains, causing chronic symptoms for many patients in the UK.

According to NHS clinical standards, approximately 50% of patients who experience a perianal abscess will go on to develop a fistula. While they are usually not life-threatening, they can be significantly uncomfortable and distressing, impacting a person's quality of life and daily activities. Understanding the symptoms early is key to receiving appropriate secondary care from a colorectal specialist.

Symptoms of an anal fistula can vary, but most patients experience a recurring cycle of discomfort. Common signs observed in UK clinical practice include:

• Skin Irritation: The skin around the anus may become red, sore, and itchy due to persistent moisture.
• Discharge: You may notice a foul-smelling discharge of pus or blood from a small opening in the skin. This often stains underwear.
• Pain: A constant, throbbing pain that often worsens when sitting down, moving around, or passing a bowel movement.
• Swelling: A tender lump may be felt near the anal opening.
• Systemic Symptoms: If a new abscess forms, you might experience a high temperature (fever) and feel generally unwell.

The vast majority of anal fistulae are caused by a perianal abscess. Small glands inside the anus can become blocked and infected, leading to an abscess. If the abscess bursts or is drained but the track fails to close properly, a fistula forms. However, there are other underlying health conditions that can increase the risk of developing a fistula in the UK:

Crohn's Disease

Inflammatory Bowel Disease (IBD), particularly Crohn's disease, is a significant risk factor. The chronic inflammation can lead to the formation of tracks between different parts of the bowel or the skin.

Diverticulitis

Infection of the small pouches in the colon can sometimes lead to complications including fistulae.

Other Factors

Relatively rare causes include complications from surgery near the anus, trauma, tuberculosis, or sexually transmitted infections (STIs) that cause rectal inflammation. NICE guidance suggests that any recurrent fistula should be investigated for underlying IBD.

A GP will typically begin the process by asking about your symptoms and medical history. A physical examination is necessary, where the doctor will look for a visible opening on the skin. They may perform a digital rectal examination (DRE) to feel the internal track. In many cases, if a fistula is suspected, the GP will refer you to a colorectal surgeon.

Specialist diagnostics in the UK often include an MRI scan or an ultrasound scan to map the path of the fistula. This is crucial as it helps the surgeon determine if the track passes through the sphincter muscles, which control bowel movements. Mapping the fistula ensures that treatment does not compromise your bowel continence.

It is important to note that anal fistulae rarely heal without medical intervention. Conservative management (wait-and-see) is usually not recommended due to the high risk of recurrent abscesses. The main surgical treatments offered by the NHS and private providers include:

• Fistulotomy: The most common procedure where the entire length of the fistula is cut open so it can heal as a flat scar. Use of this method depends on how much sphincter muscle is involved.
• Seton Procedure: If the fistula passes through a significant amount of muscle, a piece of surgical thread (a seton) is placed in the track to keep it open and allow it to drain, preventing new abscesses.
• LIFT Procedure: Ligation of the intersphincteric fistula tract is a newer technique for fistulae that pass through the sphincter muscles, avoiding cutting the muscle itself.
• Fibrin Glue or Collagen Plug: These involve sealing the track with specialized medical materials, though success rates can be lower than traditional surgery.

Discussing symptoms related to the bowel or anal area can feel embarrassing for many people. Choosing to speak to a GP online offers a discreet and comfortable environment to start the conversation. An online doctor can assess your symptoms, provide advice on managing pain and hygiene, and discuss whether a physical examination is urgent.

If you have noticed persistent discharge or recurrent pain, an online GP can facilitate a referral to an NHS or private specialist, ensuring you get on the pathway to recovery faster. Don't ignore these symptoms, as early treatment reduces the complexity of eventual surgery.

While waiting for specialist treatment, you can manage symptoms by keeping the area clean and dry. Using a sitz bath (soaking the area in warm water) for 10-15 minutes can provide relief. Over-the-counter paracetamol or ibuprofen, used according to the packet instructions, can help manage throbbing pain. Avoid using harsh soaps or scented wipes on the area, as this can worsen skin irritation.