At a glance
Anal fissures and Crohn’s disease can occur together, and when they do, the management becomes more complex. Crohn’s is a form of inflammatory bowel disease (IBD) that can affect any part of the digestive tract, including the anal canal. When the anal tissue is inflamed by Crohn’s, it is more vulnerable to tearing — and those tears may be harder to heal.
This guide covers what people need to understand about the overlap between these two conditions, how treatment approaches may differ, and when further investigation might be appropriate.
Why Crohn’s and fissures overlap
In Crohn’s disease, inflammation can occur anywhere from the mouth to the anus. Perianal involvement — meaning disease affecting the area around and inside the anus — is a well-recognised feature of Crohn’s and occurs in a significant proportion of people with the condition.
This perianal inflammation creates conditions where fissures are more likely:
- Inflamed tissue tears more easily — the lining of the anal canal is already compromised
- Diarrhoea is common — frequent loose stools can irritate and erode the anal lining
- Healing is impaired — active Crohn’s inflammation disrupts the normal healing process
- The immune response is altered — the same immune dysfunction that drives Crohn’s can affect wound repair
Typical vs atypical fissures
Standard anal fissures tend to occur in predictable locations — most commonly at the posterior midline (the back). They are usually caused by mechanical trauma from hard stools or straining.
Crohn’s-related fissures can behave differently:
- They may occur in atypical locations — lateral, anterior, or multiple positions
- They may be wider and deeper than typical fissures
- They may be painless in some cases, which is unusual for standard fissures
- They may be accompanied by other perianal features — skin tags, fistulas, abscesses
If a clinician sees a fissure in an unusual location or with unusual features, particularly in a younger person, they may consider Crohn’s as a possible underlying cause.
How treatment differs
The foundation: managing Crohn’s first
The most important difference in treating a Crohn’s-related fissure is that managing the underlying disease takes priority. If the Crohn’s is active and causing inflammation, local fissure treatments are fighting an uphill battle.
This means working with a gastroenterologist to:
- Assess the current state of the Crohn’s disease
- Optimise medical therapy — this may involve immunomodulators, biological therapies, or other disease-modifying treatments
- Monitor for disease activity in other parts of the digestive tract
When the Crohn’s is well controlled, fissures often become easier to manage.
Local treatments
Standard fissure treatments may still be part of the plan:
- Sitz baths — soothing and supportive, helpful regardless of the cause
- Stool management — fibre, hydration, and softeners remain important
- Topical relaxants — GTN or diltiazem may be used, though their effectiveness can be reduced if the underlying inflammation is not controlled
Surgery: a more cautious approach
Surgical options for fissures in Crohn’s patients are approached more carefully:
- LIS is not automatically ruled out, but surgeons weigh the healing risks more heavily. The concern is that Crohn’s can impair wound healing and that reducing sphincter tone in someone who may already have compromised continence from Crohn’s adds risk.
- Botox injection may be preferred as a less invasive option to reduce sphincter spasm.
- Fissurectomy (removing the chronic fissure tissue) may be considered in some cases.
- The decision is collaborative — involving both the gastroenterologist and the surgeon.
When to suspect Crohn’s
Most anal fissures are not caused by Crohn’s disease. But certain patterns may prompt further investigation:
- A fissure that does not heal despite adequate conservative treatment
- Fissures in unusual locations (not the posterior midline)
- Multiple fissures simultaneously
- Fissures accompanied by other perianal disease — fistulas, abscesses, large skin tags
- Associated symptoms: persistent diarrhoea, weight loss, fatigue, mouth ulcers, joint pain
- Young age at presentation with complex perianal disease
- Family history of inflammatory bowel disease
If your clinician suspects Crohn’s, they may recommend blood tests, stool tests, and potentially a colonoscopy to look at the lining of the digestive tract.
Living with both conditions
People who manage both Crohn’s and anal fissures describe it as a balancing act:
- Diet requires careful attention — some foods that help one condition may aggravate the other
- Flares affect everything — when Crohn’s flares, the fissure often worsens too
- Multiple appointments — gastroenterologist, surgeon, sometimes other specialists
- Emotional load — managing one chronic condition is hard; managing two in the same area is harder
The consistent message from people in this situation: building a relationship with both your gastroenterologist and your colorectal specialist, and making sure they communicate with each other, makes a meaningful difference.
The role of monitoring
Because Crohn’s is a chronic condition, ongoing monitoring matters:
- Regular check-ins with the gastroenterologist to assess disease activity
- Awareness of early signs of perianal disease — pain, swelling, drainage
- Prompt attention to fissure symptoms rather than waiting for them to worsen
- Open communication with the medical team about all symptoms, even ones that feel minor