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. In the UK, this is one of the most common causes of rectal pain and bleeding, affecting people of all ages. While the condition can be extremely distressing and painful, it is usually not a sign of anything more serious and often heals with appropriate self-care or medical intervention.

Fissures are categorised into two types. Acute anal fissures are fresh tears that look like a paper cut and typically heal within six weeks. Chronic anal fissures are those that persist longer than six weeks or recur frequently. Chronic cases may develop a small lump of skin, known as a 'sentinel pile' or skin tag, at the site of the tear due to long-term inflammation.

The symptoms of an anal fissure are quite distinct, though they can sometimes be confused with haemorrhoids (piles). According to NHS guidance, the hallmark signs include:

• Sharp Pain: A severe, stabbing, or 'burning' pain during bowel movements. Many patients describe it as feeling like passing shards of glass.
• Lingering Ache: A deep, throbbing ache that can last for several hours after using the toilet, caused by spasms of the anal sphincter muscle.
• Bright Red Blood: Small amounts of bright red blood on the toilet paper or the surface of the stool.
• Visible Tear: A visible crack or split in the skin around the anus.
• Itching: Irritation or pruritus around the anal area.

The primary cause of an anal fissure is trauma to the anal canal. This most commonly occurs when passing large or hard stools due to constipation. The straining involved can overstretch the anal lining, leading to a tear. Other common causes include:

• Persistent diarrhoea, which can irritate the anal mucosa.
• Childbirth, due to the intense pressure exerted during the second stage of labour.
• Inflammatory bowel disease (IBD), such as Crohn's disease.
• Tight anal sphincter muscles, which increase tension in the anal canal and reduce blood flow, making healing more difficult.

Dietary Adjustments

The first line of treatment, supported by NICE clinical knowledge summaries, involves softening the stool. Increasing your daily intake of fibre is essential. Aim for 18g to 30g of fibre per day through wholemeal bread, oats, beans, peas, and plenty of fruit and vegetables. Staying hydrated by drinking at least two litres of water daily is equally important.

The 'Sitz' Bath

Soaking the area in warm water for 10 to 15 minutes several times a day, especially after a bowel movement, can help relax the anal sphincter and improve blood flow to the area, promoting faster healing. Avoid using harsh soaps or scented products in the water, as these can further irritate the tear.

Over-the-Counter Options

You may find relief using simple analgesics like paracetamol or ibuprofen to manage the ache. Avoid codeine-based painkillers, as these frequently cause constipation, which will worsen the fissure.

If home remedies do not resolve the fissure within a few weeks, a GP may suggest prescription treatments. These are designed to reduce the pressure in the anal canal and increase blood supply.

• GTN Ointment (Glyceryl Trinitrate): A cream applied twice daily that helps the blood vessels dilate and the muscle relax. Note that a common side effect is headaches.
• Topical Calcium Channel Blockers: Creams like Diltiazem or Nifedipine work similarly to GTN but often have fewer side effects for those who cannot tolerate GTN.
• Botulinum Toxin Injections: For chronic fissures, a specialist may inject Botox into the sphincter muscle to temporarily paralyse it, allowing the tear to heal.
• Surgery (Lateral Internal Sphincterotomy): In severe cases where other treatments fail, a minor surgical procedure to cut a small section of the sphincter muscle may be required.

It is important to seek medical advice if you notice blood in your stool or experience significant rectal pain. While anal fissures are common, a professional diagnosis ensures that other conditions, such as haemorrhoids, IBD, or more serious colorectal issues, are ruled out.

Using a service like OnlineDoctor24 allows you to speak to a GP online from the privacy of your home. A doctor can review your symptoms, provide advice on lifestyle changes, and, if appropriate, issue a private prescription for GTN or Diltiazem ointment. If your symptoms are severe or suggest a chronic issue, they can also advise on the next steps for a physical examination or specialist referral.