An anal fistula is an abnormal tunnel-like connection that develops between the inside of the anal canal and the skin near the anus. This condition typically results from an infection in an anal gland that has formed an abscess. When the abscess drains, it can leave behind a small channel connecting the internal infection site to the external skin surface. Understanding the symptoms of an anal fistula is crucial for early detection and proper medical care.
While anal fistulas can be uncomfortable and distressing, recognizing the warning signs early can help you seek appropriate treatment and prevent complications. This condition affects people of all ages, though it’s more common in adults between 30 and 50 years old. Let’s explore the most common symptoms associated with anal fistulas.
1. Persistent Pain and Discomfort Around the Anus
One of the most prominent symptoms of an anal fistula is continuous or recurrent pain around the anal area. This pain typically has several distinct characteristics:
Nature of the pain: The discomfort can range from a dull, throbbing ache to sharp, intense pain. Many patients describe it as a constant burning or stinging sensation that doesn’t go away completely, even with rest.
When it worsens: The pain often intensifies during bowel movements, when sitting for prolonged periods, or during physical activities like walking, coughing, or sneezing. Some people experience relief after the fistula drains, but the pain returns as discharge accumulates again.
Impact on daily life: This persistent discomfort can significantly affect your quality of life, making it difficult to sit comfortably at work, exercise, or engage in normal daily activities. The pain may also disrupt sleep patterns, especially if you shift positions during the night.
2. Drainage of Pus or Bloody Discharge
A hallmark symptom of anal fistula is the continuous or intermittent drainage from an opening near the anus. This discharge is one of the most telling signs that distinguishes a fistula from other anal conditions.
Characteristics of the discharge: The fluid that drains from a fistula can vary in appearance. It may be:
- Clear or cloudy fluid
- Yellow or greenish pus indicating infection
- Blood-tinged or bloody discharge
- Foul-smelling drainage with an unpleasant odor
Frequency and amount: Some fistulas drain constantly, requiring frequent changes of dressings or protective pads, while others drain intermittently. The amount can range from slight spotting on underwear to substantial discharge that necessitates protective measures.
Associated concerns: The constant drainage can lead to skin irritation, hygiene challenges, and embarrassment. Many patients find they need to wear protective pads or change clothing multiple times throughout the day.
3. Visible External Opening Near the Anus
Most people with an anal fistula can identify a visible opening on the skin surface near the anus. This external opening is where the abnormal tunnel reaches the skin.
Appearance: The external opening typically appears as a small hole or dimple in the skin, usually within a few centimeters of the anal opening. The surrounding skin may be red, inflamed, and irritated due to the constant drainage. Some openings may have a slightly raised or granulated appearance.
Location: While fistulas most commonly open within 2-3 centimeters of the anus, the exact location can vary. Some may open further away or even in multiple locations if there are complex fistula tracts.
What you might notice: The area around the opening is often tender to touch, and you may notice drainage or crusting around it. The opening may occasionally close temporarily, only to reopen when pressure builds up from accumulated fluid inside the tract.
4. Swelling and Redness Around the Anal Area
Inflammation is a common symptom accompanying anal fistulas, manifesting as visible swelling and redness around the anus and the fistula opening.
Inflammatory signs: The skin around the anus and the fistula tract may appear:
- Swollen and puffy
- Red or pink in color
- Warm to the touch
- Tender when pressure is applied
Fluctuation in severity: The degree of swelling and redness often fluctuates. It may worsen when the fistula becomes blocked or infected, leading to abscess formation, and improve temporarily after drainage occurs.
Distinguishing features: Unlike hemorrhoids, which typically appear as distinct lumps, the swelling from a fistula tends to be more diffuse and associated with an obvious drainage point. The inflammation may extend along the path of the fistula tract beneath the skin.
5. Recurrent Abscess Formation
Many people with anal fistulas experience repeated episodes of abscess formation in the same area. In fact, a fistula often develops as a complication of an anal abscess that hasn’t healed properly.
Pattern of recurrence: You may notice a cycle where an abscess forms, causing severe pain and swelling, then either drains spontaneously or requires medical drainage. After temporary relief, the symptoms gradually return as another abscess develops in the same location.
Warning signs of abscess: When an abscess forms, you’ll typically experience:
- Sudden increase in pain intensity
- Increased swelling and a firm lump near the anus
- Fever and general feeling of being unwell
- Increased redness and warmth in the area
- Difficulty sitting or walking due to pain
Why it happens: The fistula tract acts as a pathway for bacteria to travel from the inside of the anal canal to the surrounding tissues, creating a cycle of infection and abscess formation. Without proper treatment of the underlying fistula, these abscesses will continue to recur.
6. Skin Irritation and Itching
The constant moisture and drainage from an anal fistula often lead to significant skin problems in the perianal area.
Causes of irritation: The continuous exposure to discharge containing bacteria, pus, and digestive enzymes causes chemical irritation to the delicate skin around the anus. This moisture prevents proper healing and creates an environment conducive to further irritation.
Symptoms you may experience:
- Persistent itching around the anus and fistula opening
- Burning sensation on the surrounding skin
- Rawness or excoriation from constant moisture
- Skin breakdown with possible oozing or weeping
- Increased sensitivity when cleaning the area
Secondary problems: Chronic skin irritation can lead to dermatitis, making the area even more uncomfortable. The itching often becomes worse at night or after bowel movements, and scratching can introduce additional bacteria, potentially worsening the infection.
7. Fever and General Malaise
When an anal fistula becomes infected or an associated abscess develops, systemic symptoms may occur, indicating that your body is fighting an infection.
Fever characteristics: You may develop a low-grade fever that comes and goes, or a higher fever during active infection or abscess formation. The fever typically indicates that bacteria from the fistula tract have triggered a more significant immune response.
Associated symptoms: Along with fever, you might experience:
- Fatigue and weakness
- General feeling of being unwell (malaise)
- Chills or sweating
- Loss of appetite
- Body aches
When to be concerned: While not everyone with an anal fistula develops fever, its presence suggests active infection that may require urgent medical attention. A high fever (above 38.5°C or 101.3°F) combined with severe pain and swelling is a warning sign that should not be ignored.
Main Causes of Anal Fistula
Understanding what causes anal fistulas can help you recognize risk factors and potential preventive measures. Here are the primary causes:
Anal Abscess: The most common cause of anal fistula is a previous anal abscess. Approximately 50% of people who have had an anal abscess will develop a fistula. The abscess forms when anal glands become blocked and infected, creating a pocket of pus. When this abscess drains or is surgically drained, it may leave behind a fistula tract.
Inflammatory Bowel Disease (IBD): Conditions like Crohn’s disease significantly increase the risk of developing anal fistulas. About 25% of people with Crohn’s disease will develop a fistula at some point. The chronic inflammation characteristic of these conditions can lead to abnormal connections between tissues.
Trauma or Injury: Physical trauma to the anal area from accidents, childbirth complications, or surgical procedures can create conditions favorable for fistula formation.
Infections: Various infections can lead to fistula development:
- Tuberculosis affecting the intestinal tract
- Sexually transmitted infections
- Diverticulitis complications
- Hidradenitis suppurativa (chronic skin condition)
Previous Surgery: Surgical procedures in the anal or rectal area, including hemorrhoid surgery or anal fissure repair, can occasionally result in fistula formation as a complication.
Cancer or Radiation Treatment: Though less common, anal or rectal cancer, as well as radiation therapy to the pelvic area, can contribute to fistula development.
Other Medical Conditions: Diabetes, compromised immune system, chronic diarrhea, and conditions causing chronic constipation can increase the risk of developing anal fistulas.
Prevention Strategies
While not all anal fistulas can be prevented, especially those related to chronic conditions, there are several strategies that may help reduce your risk:
Maintain Good Anal Hygiene: Keep the anal area clean and dry. After bowel movements, gently clean the area with water or mild, unscented wipes. Pat dry thoroughly rather than rubbing. Avoid harsh soaps or perfumed products that can irritate the delicate skin.
Prevent Constipation and Straining: Chronic straining during bowel movements can increase pressure in the anal area and potentially lead to problems:
- Eat a high-fiber diet with plenty of fruits, vegetables, and whole grains
- Stay well-hydrated by drinking adequate water throughout the day
- Exercise regularly to promote healthy bowel function
- Don’t delay when you feel the urge to have a bowel movement
Seek Prompt Treatment for Anal Problems: If you develop symptoms of an anal abscess (severe pain, swelling, fever), seek medical attention immediately. Early and proper treatment of abscesses may prevent fistula formation.
Manage Underlying Conditions: If you have inflammatory bowel disease, diabetes, or other chronic conditions, work closely with your healthcare provider to keep them well-controlled. Proper management of Crohn’s disease, in particular, can reduce the risk of fistula complications.
Safe Sexual Practices: Practice safe sex to prevent sexually transmitted infections that could potentially lead to anal complications.
Avoid Prolonged Sitting: If your job requires extended periods of sitting, take regular breaks to stand and move around. This helps reduce pressure on the anal area.
Healthy Lifestyle Choices: Maintain a healthy weight, avoid smoking, and limit alcohol consumption. These lifestyle factors support overall immune function and tissue healing.
Frequently Asked Questions
Can an anal fistula heal on its own without treatment?
Unfortunately, anal fistulas very rarely heal on their own. They almost always require medical or surgical intervention. Without treatment, the fistula will typically persist, causing ongoing symptoms and potential complications. If you suspect you have a fistula, it’s important to consult a healthcare provider for proper evaluation and treatment.
How is an anal fistula diagnosed?
Diagnosis typically begins with a physical examination where your doctor inspects the area around your anus for the external opening. They may gently probe the area to assess the fistula tract. Additional tests may include anoscopy (examination of the anal canal), MRI scans, or fistulography to map the complete fistula tract, especially if it’s complex.
Are anal fistulas contagious?
No, anal fistulas themselves are not contagious. However, if the fistula is caused by an infection such as a sexually transmitted disease, that underlying infection could potentially be transmitted. The fistula itself is a structural problem and cannot be passed from person to person.
Can I still have bowel movements normally with an anal fistula?
Most people with anal fistulas can still have bowel movements, though it may be uncomfortable or painful. Some people notice increased discharge during or after bowel movements. It’s important to maintain soft, regular stools to minimize discomfort. If you’re having significant difficulty with bowel movements, consult your healthcare provider.
What’s the difference between an anal fistula and hemorrhoids?
Hemorrhoids are swollen blood vessels in the anal area that cause lumps, bleeding, and discomfort but don’t typically involve drainage of pus. Anal fistulas are abnormal tunnels with persistent drainage, often with an infection component. While both can cause pain and occur in the same area, they are distinct conditions requiring different treatments.
How long do anal fistula symptoms last?
Without treatment, anal fistula symptoms typically persist indefinitely and may fluctuate in severity. You might experience periods of improvement when the fistula drains well, alternating with worsening symptoms when it becomes blocked or infected. The symptoms will continue until the fistula is properly treated.
Should I see a doctor if I think I have an anal fistula?
Yes, absolutely. If you experience persistent drainage, pain, or notice an opening near your anus, you should consult a healthcare provider. Early diagnosis and treatment can prevent complications and provide relief from uncomfortable symptoms. Don’t let embarrassment prevent you from seeking care—anal fistulas are a common medical condition that doctors treat regularly.
Can anal fistulas lead to serious complications?
If left untreated, anal fistulas can lead to several complications including recurrent abscesses, development of multiple fistula tracts, fecal incontinence (in rare cases involving muscle damage), and chronic infection. Very rarely, long-standing fistulas associated with inflammatory bowel disease may have an increased risk of cancer, though this is uncommon.
References:
- Mayo Clinic – Anal Fistula
- NHS – Anal Fistula
- NCBI – Anal Fistula
- American Society of Colon and Rectal Surgeons – Anal Fistula
- Johns Hopkins Medicine – Anal Fistula
The information on this page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions related to your health.
Read the full Disclaimer here →