Introduction

An anal fissure is a tear in the tissue that lines the anal canal.¹ Anal fissures are usually related to anal trauma. Anal pain and bleeding are the most common symptoms of anal fissures. Anal fissures are most commonly seen in middle-aged and younger patients.² Anal fissures particularly recurrent could be evidence of sexual abuse.³ Most anal fissures resolve with simple treatments, such as increased fibre intake or sitting in warm water. However, some people with anal fissures may need medications or surgery.

What is an anal fissure?

An anal fissure is a tear in the tissue that lines the anal canal.¹ The anal canal is a muscular tube at the end of your gastrointestinal tract through which the stool exits your body. Anal fissures are usually related to anal trauma from constipation, straining, and passing hard or large stools. Posterior anal fissures are more common than anterior ones due to poor blood supply to this location. Most anterior anal fissure occurs in females from childbirth.

What are the symptoms of anal fissures?

• Pain with the passage of stools (resembling passing broken glass) lasted several minutes to hours
• Bright red blood on the stool (usually a small amount of blood)
• Itching around your anal fissure
• Spasms of anal sphincter
• Discomfort while sitting or riding with persistent thorn-like feeling in the anus
• A crack can be seen in the skin around the anus
• A lump of skin near the fissure

What causes anal fissures?

The exact cause of anal fissures is still unknown. However, anal fissures may be related to anal trauma or other conditions.

Common causes of anal trauma

• Passage of hard or large stools
• Constipation and straining
• Long-lasting diarrhoea
• Anal intercourse
• Repeated hitting of the anus by water stream
• Childbirth
• Prior anal surgery

Some medical conditions that may increase the risk of anal fissures include;

• Inflammatory bowel disease such as Crohn’s disease
• Tuberculosis
• Human immunodeficiency virus (HIV)
• Syphilis
• Chemotherapy
• Anal cancer
• Most  individual's living with anal fissures have a persistently high anal sphincter tone. High anal sphincter tone reduces blood flow and prevents the fissure from healing⁴ 

How to diagnose anal fissures?

Your healthcare provider will ask you about the symptoms and then try to see the anal fissure. To see the anal fissure the healthcare provider will gently separate your buttocks. If the pain is tolerable the healthcare provider will insert a lubricated gloved finger into the anal canal to examine it. If the cause of the anal fissure is uncertain, examination under anesthesia, anoscopy, endoscopy, biopsy, and imaging (such as CT scan, MRI, or endoanal ultrasound) may be required.

How to treat anal fissures?

Most anal fissures heal within a few days to weeks, however,majority of anal fissures may resolve with non-surgical treatment.

Non-surgical treatment

Symptom relief

• Sit in warm water
• Topical anesthetic creams such as lidocaine may help relieve the pain of anal fissures⁵ 
• Anal self-massage with the patient’s lubricated index finger in a circular motion for 10 min twice a day⁶ 

Medications

Work by relaxing the anal sphincter.

• Nitroglycerin ointment promotes anal fissure healing by increasing blood flow to the fissure and relaxing the anal sphincter. Side effects may include redness and itching around the anus⁷ 
• Calcium channel blockers, such as diltiazem or nifedipine, are an alternative way of increasing blood flow to the fissure and relaxing the anal sphincter. Side effects may also include skin redness around the anus.⁷ Used if nitroglycerin doesn’t work
• Botox injection into anal sphincter muscles under general anesthesia. The effect of Botox injection relaxes the anal sphincter muscles for up to 3 to 4 months. The most common side effect of botox injection is transient soiling during the first few weeks after treatment.⁸ Used if nitroglycerin ointment and calcium channel blockers don’t work

Mechanical anal dilatation under local anesthesia

• Endoscopic anal dilatation⁹ 
• Balloon anal dilatation by inflating a balloon inside the anal canal and then the balloon is left for six minutes¹⁰ 

Treating the underlying cause

By treating constipation and straining and avoiding causes of anal trauma such as anal sex. Constipation can be treated by the following:

• Stool softeners such as polyethylene glycol or lactulose. It is important to continue using stool softeners for some time after the fissure has healed to reduce the risk of recurrence of anal fissures¹¹ 
• Increase fluid and fibre intake. Partially hydrolyzed guar gum (rich in fibres) 5 g/day for 10 months lowers the risk of recurrence. However, side effects such as abdominal distension and flatulence may cause interruption of treatment¹² 

Surgical treatment

Surgery is used if non-surgical treatment for over 6–8 weeks does not produce desired results.

Lateral internal sphincterotomy

In lateral internal sphincterotomy (LIS) a lateral small cut is made in the tissue line of the anal canal and anal sphincter. The most common side effect of anal surgery is fecal incontinence.

Complications

• Chronicity: An anal fissure that fails to heal within six weeks is considered a chronic anal fissure and may need further treatment
• Recurrence of anal fissures
• An anal fissure may extend into the internal anal sphincter

Prevention

• Treat constipation or diarrhoea
• Drink more fluids
• Eat more high-fibre foods
• Exercise regularly

Summary

An anal fissure is a tear in the tissue that lines the anal canal.¹ Common causes of anal fissures include constipation, straining, and passing hard or large stools. Symptoms of anal fissures include pain and bleeding with the passage of stools. The majority of acute anal fissures resolve by non-surgical treatment such as sitting in a warm bath, nitroglycerin ointment, calcium channel blockers, Botox injections, topical anesthetic creams, and endoscopic and ballon anal dilatation.

Surgery is used if non-surgical treatment for over 6–8 weeks does not produce desired results. In lateral internal sphincterotomy (LIS) a lateral incision is made in the tissue line of the anal canal and anal sphincter.