Anal fissure
An anal fissure is a small tear in the thin, moist tissue (mucosa) that lines the anus. It often causes sharp pain and bright red bleeding during or after bowel movements.
Overview
An anal fissure is a small tear in the thin, moist tissue (mucosa) that lines the anus. It often causes sharp pain and bright red bleeding during or after bowel movements.
Understand this condition
The anal canal is lined with a delicate membrane that can stretch but may tear under pressure. When a tear occurs, the internal anal sphincter muscle often goes into spasm. This spasm reduces blood flow to the injury and makes healing more difficult.
Why it happens
Fissures usually happen when the skin is stretched beyond its capacity, often by hard stool. The primary trigger is constipation, which creates a cycle of injury and painful muscle spasms. If the muscle remains tight, the wound cannot receive enough oxygenated blood to repair itself.
Real-world scenarios
- •People may notice sharp, knife-like pain during a bowel movement.
- •This often appears as bright red blood on the toilet tissue.
- •Someone may notice a small visible crack in the skin near the anus.
- •People may experience a lingering ache or burning sensation after using the bathroom.
Common vs serious explanations
- •Hard stools caused by a low-fiber diet
- •Dehydration leading to temporary constipation
- •Temporary irritation from frequent diarrhea
- •Minor trauma from rough wiping or hygiene habits
- Anal cancer or other rectal malignancies
- Crohns disease or Ulcerative Colitis complications
- Anal fistula or localized abscess formation
- Sexually transmitted infections such as syphilis or HIV
Symptoms
Click any symptom to analyzeNo symptoms mapped yet.
Causes
- •Passing large or hard stools
- •Chronic constipation or straining during bowel movements
- •Chronic diarrhea
- •Anal intercourse or trauma
- •Inflammatory bowel disease (IBD) such as Crohn's disease
Risk factors
- •Infancy or older age
- •Chronic constipation
- •Childbirth
- •Crohn's disease
How it progresses
3 stages- OnsetSymptoms appear, often triggered by a known cause.Often missed
- Active phaseSymptoms peak; self-care or short treatment usually helps.
- ResolutionSymptoms ease over days to weeks with proper care.
How it's diagnosed
- •Physical examination of the anal area
- •Digital rectal exam
- •Anoscopy
- •Sigmoidoscopy or colonoscopy (to rule out underlying conditions)
Treatment options
General educational information only — no dosage advice. Always follow guidance from a qualified clinician.
- •Topical nitroglycerin or calcium channel blocker ointments
- •Over-the-counter stool softeners
- •Botulinum toxin (Botox) injections
- •Lateral internal sphincterotomy (surgery) for chronic cases
- •Increasing dietary fiber intake (25-35 grams daily)
- •Taking warm sitz baths for 10-20 minutes several times a day
- •Using stool softeners or fiber supplements
- •Drinking plenty of water to stay hydrated
- •Avoiding straining during bowel movements
- •High-fiber diet and hydration
Complications
- •Reduced quality of life
- •Worsening symptoms over time
- •Recurrence of anal fissure
Prevention
- •Wash hands frequently
- •Avoid close contact with infected people
- •Stay up to date with vaccines
- •Maintain a healthy lifestyle
- •See a clinician for routine check-ups
When to seek help
- •Symptoms persist beyond a few days
- •Symptoms interfere with daily activities
- •New or worsening symptoms appear
- •Concerning changes related to anal fissure
- Extreme or worsening rectal pain
- Heavy Rectal bleeding or large blood clots
- High fever or chills
- Pus drainage from the fissure (possible abscess)
In any emergency, call your local emergency number or go to the nearest emergency department.
Real-world questions
- ›Can Anal fissure cause headaches?
- ›Is Anal fissure reversible?
- ›How quickly does Anal fissure progress?
- ›Is Anal fissure hereditary?
- ›Can Anal fissure be prevented?
Compare conditions
Explore related symptoms
Frequently asked questions
Possible causes of Anal fissure include Passing large or hard stools, Chronic constipation or straining during bowel movements, Chronic diarrhea, Anal intercourse or trauma.
Anal fissure is generally mild, but severity can vary. Seek care if symptoms are severe or persistent.
Duration varies between individuals. Many cases improve with appropriate care, while others may persist longer and require ongoing management.
Some milder cases may improve with rest and self-care. If symptoms persist or worsen, consult a healthcare professional.
Consider seeing a clinician if symptoms are severe, persistent, worsening, or if you have any concerns related to general.
Sources
Information based on general medical references such as:
Last reviewed: May 2026