Anal fissure
Table of Contents
Key takeaways
- An anal fissure is a small split or tear in the skin lining the anus. It often follows constipation or passing a large, hard stool, but it can also happen after diarrhoea, childbirth, anal sex, inflammatory bowel disease or infection. Fissures can be intensely painful despite being small because the anal canal has many sensitive nerve endings.
- When the skin tears, the internal anal sphincter can go into spasm. Spasm reduces blood flow to the tear and makes pain worse during and after a bowel movement. This creates a cycle: pain leads to stool withholding, withholding worsens constipation, and constipation stretches the area again. Breaking that cycle is central to management.
- Assessment matters because similar symptoms can have different causes, and treatment should be matched to the confirmed diagnosis and personal risk factors.
- Seek medical advice for rectal bleeding, severe pain, fever, pus, a lump, black stools, weight loss, change in bowel habit, symptoms after anal sex with possible infection risk, or fissures that do not improve. Use NHS 111 for urgent advice if pain is severe or infection is suspected, and call 999 for heavy bleeding, collapse or a life-threatening emergency.
Article type
medical_condition
Overview
An anal fissure is a small split or tear in the skin lining the anus. It often follows constipation or passing a large, hard stool, but it can also happen after diarrhoea, childbirth, anal sex, inflammatory bowel disease or infection. Fissures can be intensely painful despite being small because the anal canal has many sensitive nerve endings.
When the skin tears, the internal anal sphincter can go into spasm. Spasm reduces blood flow to the tear and makes pain worse during and after a bowel movement. This creates a cycle: pain leads to stool withholding, withholding worsens constipation, and constipation stretches the area again. Breaking that cycle is central to management.
This article is written as a practical medical guide rather than a short definition. It covers what the condition may feel like, why it happens, which risk factors are relevant for women and families, how clinicians assess it, what treatment may involve, and when symptoms should be escalated. The aim is to support informed conversations with a GP, pharmacist, specialist clinician or emergency service, not to replace individual assessment.
Symptoms and reader concerns
Symptoms can vary in intensity, duration and impact. Some people have a clear textbook pattern, while others have subtle, overlapping or intermittent symptoms. Keep track of timing, triggers, severity, medicines, pregnancy or menopause context where relevant, and how symptoms affect sleep, work, sex, caring responsibilities or exercise.
- sharp pain during a bowel movement, sometimes followed by burning or throbbing for hours.
- bright red blood on toilet paper or on the outside of the stool.
- a visible split, small skin tag or tenderness around the anus.
- fear of opening the bowels because pain is expected.
- itching, irritation or discharge if the area is inflamed or healing slowly.
Symptoms that are new, persistent, one-sided, severe, linked with bleeding, breathing difficulty, fainting, pregnancy, neurological changes or rapid deterioration should be assessed promptly. It is also worth seeking help when symptoms keep returning despite reasonable self-care, because repeated episodes may indicate an underlying cause that needs targeted treatment.
Causes and risk factors
The underlying mechanism is important because it guides safe treatment. When the skin tears, the internal anal sphincter can go into spasm. Spasm reduces blood flow to the tear and makes pain worse during and after a bowel movement. This creates a cycle: pain leads to stool withholding, withholding worsens constipation, and constipation stretches the area again. Breaking that cycle is central to management.
Risk factors do not mean someone has caused the condition. They simply help clinicians decide what to ask about, what to test, what complications to consider and which prevention steps are realistic.
- constipation, hard stools, low fluid intake or straining.
- recurrent diarrhoea, inflammatory bowel disease or anal infections.
- pregnancy, childbirth and pelvic floor changes after birth.
- previous fissures, reduced blood flow to the area or tight sphincter spasm.
- anal trauma, including sex or insertion, especially without adequate lubrication and comfort.
Women may also need context-specific review around heavy periods, pregnancy and birth, contraception, hormone therapy, menopause timing, pelvic symptoms, autoimmune disease or previous cancer treatment. Those details can change both the likely cause and the safest management options.
Diagnosis and assessment
Diagnosis is usually made from the history and a gentle visual examination. A digital rectal examination may be delayed if pain is severe. Clinicians should consider other causes of anal pain or bleeding, including haemorrhoids, abscess, inflammatory bowel disease, sexually transmitted infections and, rarely, cancer. Persistent, recurrent, atypical or non-healing fissures need review rather than repeated self-treatment.
A useful appointment history includes when symptoms started, whether they are improving or worsening, what has already been tried, current medicines and supplements, allergies, relevant family history and any red flags. If symptoms affect intimate health, bowel habits, periods, fertility, pregnancy or mental wellbeing, it is appropriate to say so clearly; these details are clinical information, not personal failings.
Testing should be proportionate. Some conditions are diagnosed mainly from symptoms and examination, while others need blood tests, imaging, swabs, endoscopy, ultrasound or specialist referral. If a test result is normal but symptoms continue, follow-up can still be appropriate because a single test rarely answers every clinical question.
Treatment and management
Treatment focuses on soft stools, pain control and sphincter relaxation. Options may include stool softeners or laxatives, adequate fluids, fibre, topical anaesthetic for short-term pain, and prescribed ointments that relax the sphincter. Chronic fissures may need specialist colorectal assessment, injections into the sphincter or surgery if conservative measures do not work. Suitability is confirmed after consultation, especially during pregnancy or breastfeeding.
Good management balances symptom relief with safety. Medicines, procedures and monitoring can be helpful, but they should be chosen with the confirmed diagnosis, medical history, pregnancy or breastfeeding status, other medicines and personal preferences in mind. Ask what benefit is expected, how quickly improvement should be noticed, what side effects to watch for, and what to do if symptoms do not improve.
For longer-term conditions, follow-up is part of care rather than a sign that treatment has failed. Reviews can check whether the diagnosis still fits, whether complications are developing, whether medicines remain suitable, and whether additional support such as physiotherapy, dietetic input, psychological support, specialist nursing or consultant review is needed.
Self-care and prevention
Helpful measures include not delaying bowel movements, avoiding straining, using a footstool to improve toilet posture, bathing the area in warm water, and using soft toilet paper or water-based cleansing. Increase fibre gradually to avoid bloating, and drink enough fluid. Avoid repeatedly using unverified creams or harsh wipes, because irritation can delay healing.
Prevention advice should be realistic and evidence-informed. It may reduce risk or symptom burden, but it should not be framed as a personal responsibility to prevent every flare, complication or recurrence. If recommended self-care is unaffordable, impractical or clashes with work, disability, caring responsibilities or cultural needs, discuss alternatives with a clinician or pharmacist.
Avoid relying on unverified home remedies for persistent or severe symptoms. Some products can irritate skin, interact with medicines, delay diagnosis or be unsuitable in pregnancy, breastfeeding, kidney disease, liver disease, diabetes or when taking anticoagulants. Pharmacy advice can be a useful first step for mild symptoms, but it has limits when red flags are present.
When to seek medical advice
Seek medical advice for rectal bleeding, severe pain, fever, pus, a lump, black stools, weight loss, change in bowel habit, symptoms after anal sex with possible infection risk, or fissures that do not improve. Use NHS 111 for urgent advice if pain is severe or infection is suspected, and call 999 for heavy bleeding, collapse or a life-threatening emergency.
Bring a list of medicines, supplements, allergies and relevant diagnoses to appointments. If symptoms are intermittent, photographs, home readings, a diary or a written timeline can help, provided this is safe and does not delay urgent care. If you feel dismissed and symptoms are worsening or affecting daily life, asking for review or a second opinion is reasonable.
Sources
- NHS, Anal fissure: https://www.nhs.uk/conditions/anal-fissure/
Relevance: Supports symptoms, causes, treatment and self-care advice for anal fissure. - NICE CKS, Anal fissure: cks.nice.org.uk guidance page link unavailable during validation (cks.nice.org.uk guidance page, link unavailable during validation)
Relevance: Supports assessment, red flags and primary-care management. - NHS, Constipation: https://www.nhs.uk/conditions/constipation/
Relevance: Supports stool-softening and self-care advice relevant to fissure prevention. - Mayo Clinic, Anal fissure: mayoclinic.org guidance page link unavailable during validation (mayoclinic.org guidance page, link unavailable during validation)
Relevance: Used as a benchmark for symptoms, causes, diagnosis and treatment completeness.
Disclaimer
Educational only. Results vary. Not a cure.