Anal fissure

What is an anal fissure?

An anal fissure is a small tear in the skin and lining at the anal opening. It usually sits at the back and can cause sharp, intense pain, particularly when you open your bowels. You may notice a little fresh red blood on the paper or on the stool, and the pain can carry on for hours after a visit to the toilet.

The pain does not come from the tear alone. The internal sphincter muscle can also go into spasm. That spasm reduces the blood supply to the area and makes it harder for the tear to heal.

Most fissures can be treated without surgery.

Typical symptoms

• Sharp, burning or cutting pain when opening your bowels.
• Pain lasting from minutes to several hours after using the toilet.
• A little fresh red blood on the toilet paper or on the stool. Read more about blood in stool.
• Fear of opening the bowels, which easily leads to constipation.

These symptoms can look like other bowel conditions. We therefore examine you before treatment starts, and if there is any doubt or other warning signs, a bowel examination (colonoscopy) may be relevant.

Fissure or haemorrhoids?

The two conditions are easily confused. The character and timing of the pain usually differ.

Feature	Anal fissure	Haemorrhoids
Pain	Sharp, cutting pain during and especially after a bowel movement	More often pressure, irritation and itching than true pain
Duration	Pain can last well beyond the toilet visit	Symptoms tend to come in episodes of swelling or prolapse
Bleeding	Small amounts of fresh blood	May bleed bright red, often without pain

An acutely thrombosed external haemorrhoid, where a blood clot has formed in an external haemorrhoid, can however be very painful. A fissure typically causes sharper pain that lingers after a bowel movement.

When a fissure is not in the usual place

Most fissures sit in the midline, usually at the back. If the tear sits somewhere else, or behaves differently from expected, it should be assessed by a doctor again rather than simply carrying on with routine local treatment.

Ask for a new medical assessment if:

• the tear sits off to the side (laterally) rather than in the midline
• there is more than one tear
• the tear looks different from a typical fissure, for example with undermined edges or raised margins
• the tear has not healed within the agreed treatment period
• you develop fever or pus
• there is significant bleeding
• you are losing weight without explanation
• your immune system is weakened, for example by medicine after a transplant, chemotherapy or other immunosuppressive treatment.

This does not mean something serious is going on. But in those situations the doctor needs to consider whether another cause lies behind it, for example inflammatory bowel disease, an infection or, more rarely, a local cancer. That is settled with an examination, not with more of the same ointment.

How long does healing take?

Many people feel better within 2-4 weeks. Full healing often takes 6-12 weeks. Some need a longer course of treatment as agreed with the doctor.

We normally arrange a review after about 4 weeks of treatment. Always keep to the agreed dose and duration for each product.

Treatment step by step

At Kirurgen.dk the local treatments are used in the order below. The choice depends on your symptoms, on the effect so far and on the doctor's assessment.

1. Diltiazem gel

First choice. The gel relaxes the sphincter muscle and gives the tear a better chance to heal. Use the amount and frequency your doctor has prescribed for you. Contact the clinic if side effects bother you.

Diltiazem is not available in Denmark as a licensed, marketed medicine for anal fissure. The gel is prescription-only and pharmacy-compounded (magistral), made up at the pharmacy for the individual patient. Supply, strength and price can therefore differ from an ordinary over-the-counter ointment, and the prescription is renewed through the clinic or your GP.

2. Rectogesic ointment

Can be used if diltiazem does not help enough or is not tolerated. Use the ointment as prescribed. It can cause headache.

3. Levorag rectal tube

Can be used as the next local treatment if symptoms continue. Levorag is a single-use tube with a long rectal applicator. Follow the instructions you have been given.

Levorag is registered as a medical device, not as a medicine. The evidence behind it is more limited than for diltiazem and Rectogesic, so it is used as a supplementary local option.

4. When is Botox considered?

A Botox injection may be considered if the fissure has not healed or pain persists despite correct local treatment for about 6-8 weeks, or in a chronic fissure. The doctor assesses whether it is right for you.

Botulinum toxin (Botox) temporarily relaxes the internal sphincter muscle, giving the tear a better chance to heal. Some people find for a while that it is harder to hold gas or loose stool. These symptoms are usually temporary, because the effect on the muscle wears off by itself. We go through the pros and cons with you before treatment is agreed.

5. When is surgery considered?

Surgery may be considered for a severe or chronic fissure when the other treatments, and possibly Botox, have not been enough. The options are discussed with the doctor.

The procedure is called lateral internal sphincterotomy (LIS), where part of the internal sphincter muscle is divided. The healing rate is high, but the procedure can affect continence, most often as difficulty holding gas or minor leakage, and in some cases the effect can persist. Reported rates vary widely between studies because definitions, surgical technique and follow-up differ, and the figures also include mild and temporary symptoms. We therefore do not quote a single number.

The choice is always an individual assessment. Among other things we look at whether you already have trouble controlling gas or stool, have inflammatory bowel disease, have had an obstetric or other sphincter injury, or have had previous surgery in the anal area. Risk assessment deserves particular care in women because anatomy and any previous obstetric injury may increase the risk to continence; this does not mean that every woman has the same risk. If one or more risk factors apply, other options may be more suitable, such as continued medical treatment, botulinum toxin or a flap procedure. A flap procedure is a possible specialist treatment, not a promise that it is offered at this clinic. We discuss the benefits and drawbacks with you before making a plan.

Do not change your treatment on your own. Follow the clinic's instructions on product, dose and duration.

What you can do yourself

Treatment takes patience. Soft stools and regular use of the prescribed treatment are an important part of the course.

• Keep the stool soft. Drink plenty, eat fibre if you tolerate it, and use a laxative if agreed with the doctor.
• Avoid straining on the toilet. Keep up the good bowel habits, also once the pain has eased.
• Warm sitz baths can relieve symptoms. Clean the area gently and avoid heavy rubbing.
• Use your treatment regularly and for the period agreed with the clinic.

Contact the clinic if

• the pain increases markedly, or you develop fever or pus
• the bleeding becomes clearly heavier
• you notice no improvement within the agreed period.

If it cannot wait

Most fissure symptoms can wait until ordinary phone hours. Some situations need to be assessed the same day:

• Heavy bleeding, or if you become pale, dizzy or develop palpitations: call 112.
• New swelling, fever or suddenly increasing pain, which can be a sign of an abscess: seek assessment the same day, outside phone hours via 1813 in the Capital Region or your local out-of-hours service.
• You cannot pass urine, or the pain cannot be controlled with what you have been prescribed: contact a doctor the same day.

Email is not an emergency channel and is not read outside opening hours.

Sources

• Davids JS et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anal Fissures. Diseases of the Colon & Rectum 2023;66(2):190-199. Abstract in PubMed.
• Cross KLR et al. The Association of Coloproctology of Great Britain and Ireland guideline on the management of anal fissure. Colorectal Disease 2023. Read the guideline via DOI.
• Lægehåndbogen (the Danish physicians' handbook), Analfissur, sundhed.dk, updated 8 May 2025.
• Patienthåndbogen (the Danish patient handbook), Analfissur, sundhed.dk, updated 16 October 2024.
• Peter Christensen (author) and Lilli Lundby (reviewer), Haemorrhoids and anal fissure, pro.medicin.dk.

This page is patient information and does not replace a medical assessment of your own symptoms.