Anal Fissures: Symptoms, Causes, and Effective Treatment in the UK

An anal fissure is a small tear or cut in the thin, moist tissue (mucosa) that lines the anus. While it may seem like a minor injury, the location makes it particularly sensitive and prone to reopening. In the UK, it is a common digestive health concern that affects people of all ages, often mistaken for haemorrhoids (piles).

Fissures are categorised as either acute (present for less than six weeks) or chronic (persisting for longer than six weeks). Chronic fissures often develop a small skin tag at the base, known as a 'sentinel pile'. According to NICE (National Institute for Health and Care Excellence), most acute fissures will heal with self-care and pharmacy-level treatment, but chronic cases usually require medical intervention to prevent long-term discomfort.

The symptoms of an anal fissure are distinct, though they can overlap with other bowel conditions. The most common signs reported by British patients include:

• Sharp pain: Often described as feeling like 'passing shards of glass' during a bowel movement.
• Post-defecation ache: A burning or throbbing pain that can last for several hours after visiting the toilet.
• Bright red blood: You may notice small amounts of bright red blood on the toilet paper or on the surface of the stool. Unlike internal bleeding, this blood is typically vivid red.
• Visible tear: A visible crack in the skin around the anus.
• Anal spasms: The internal sphincter muscle may spasm, which causes intense pain and prevents the tear from healing by restricted blood flow.

The most frequent cause of an anal fissure is trauma to the anal canal. This usually occurs during constipation, when passing particularly large, hard, or dry stools. The stretching required to pass the stool causes the mucosa to tear.

Other potential causes include:

• Persistent diarrhoea, which can irritate the anal lining.
• Childbirth, due to the intense pressure on the perineal area.
• Inflammatory bowel diseases (IBD) such as Crohn’s disease.
• Increased tension in the internal anal sphincter muscle, which reduces blood flow to the area and slows healing.

In the UK, diet plays a significant role; a lack of dietary fibre is the leading contributor to the constipation that triggers these tears.

Following NHS and NICE guidelines, the first line of treatment involves softening the stools to allow the tear to heal naturally. This includes:

Self-Care and Lifestyle

• High-fibre diet: Increasing intake of whole grains, fruits, and vegetables.
• Hydration: Drinking plenty of water to prevent hard stools.
• Bulk-forming laxatives: Such as ispaghula husk, to make stools softer and easier to pass.
• Sitz baths: Soaking the area in warm water for 10–15 minutes several times a day to relax the sphincter muscle.

Medical Treatments

If self-care is insufficient, a doctor may prescribe:

• Topical Anaesthetics: Creams containing lidocaine to numb the area before a bowel movement.
• GTN Ointment (Glyceryl Trinitrate): A prescription-only cream that helps expand blood vessels and relax the muscle, promoting healing.
• Diltiazem or Nifedipine creams: Calcium channel blockers used off-label in the UK to relax the anal muscle with fewer side effects than GTN.

Many patients feel embarrassed about rectal symptoms, but anal fissures are a routine concern for healthcare professionals. You should speak to a GP online in the UK if:

• Your symptoms have not improved after two weeks of home treatment.
• The pain is so severe it interferes with your daily activities.
• You are experiencing recurrent bleeding (it is vital to confirm the source of any rectal bleeding).
• You have developed a chronic fissure that requires a prescription for GTN or Diltiazem.

An online consultation allows you to discuss your symptoms in a calm, private environment. A GP can review your medical history, provide advice on stool softeners, and issue private prescriptions to help accelerate the healing process.

If a fissure fails to heal after 6–8 weeks of medical treatment, it is considered chronic. In these cases, a GP may refer you to a colorectal surgeon. Specialist treatments in the UK include Botulinum toxin (Botox) injections into the sphincter muscle to induce relaxation, or a minor surgical procedure called a Lateral Internal Sphincterotomy. This surgery involves making a small cut in the sphincter muscle to reduce tension, boasting a high success rate for permanent healing.