Skip to main content

Health condition · Clinically reviewed

IBD complications, from strictures and fistulae to joints, skin and eyes.

Inflammatory bowel disease reaches beyond the gut. This guide sets out the complications that matter, how they are found and how they are managed within a specialist commissioned IBD service.

Jump to management
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against BSG, ECCO, NICE and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK IBD care including advanced biologics, JAK inhibitors and dysplasia surveillance.

Key facts

IBD complications at a glance.

The essentials, in plain English - what they are, where they show up and who leads the care.

  • What it means

    The intestinal and extra-intestinal problems that can arise from Crohn's disease and ulcerative colitis, and from the medications used to treat them.

  • Intestinal

    Strictures, fistulae, abscesses, toxic megacolon, colorectal cancer risk, short-bowel syndrome and dysplasia.

  • Extra-intestinal

    Joints, skin, eyes, liver and blood - roughly a third of patients experience at least one manifestation.

  • Perianal disease

    A distinct Crohn's phenotype - fistulae, fissures and abscesses needing MRI, EUA and combined medical-surgical care.

  • Medication risks

    Infection, TB reactivation and, with thiopurines, a small excess risk of lymphoma and skin cancer.

  • Who manages it

    A specialist commissioned IBD MDT - gastroenterology, colorectal surgery, radiology, dermatology, rheumatology and hepatology.

Why this guide matters

A whole-body condition, not just a gut disease.

Whether it is Crohn\'s disease or ulcerative colitis, the complications reach well beyond the bowel. The three ideas below shape everything else here.

  • Recognise the pattern early

    A stricture, fistula or new joint pain rarely arrives alone - each is a clue to bowel activity and to the whole plan.

  • Treat the disease, not just the flare

    Advanced therapies and structured surveillance reduce hospital admissions, surgery and cancer risk over time.

  • Coordinated MDT care wins

    Specialist commissioned IBD services bring gastroenterology, surgery, radiology and allied specialists into one plan.

How complications are identified

From symptom change to a clear plan.

The steps a UK IBD service will normally follow, in order, when a new problem is suspected in a patient with inflammatory bowel disease.

  1. 01

    Assessing

    History and phenotype

    Duration, Montreal classification, current and prior therapies, surgical history and any red-flag symptoms since the last review.

  2. 02

    Assessing

    Targeted examination

    Abdomen, perianal inspection, joints, skin and eyes - each can flag a different complication.

  3. 03

    Assessing

    Baseline bloods

    FBC, CRP, ferritin, B12, folate, LFTs and faecal calprotectin - iron, B12 and PSC screens matter here.

  4. 04

    Confirming

    MRI enterography

    A specialist commissioned scan for strictures, fistulae and disease activity - the workhorse for Crohn's complications.

  5. 05

    Confirming

    Endoscopy and dysplasia surveillance

    Colonoscopy with chromoendoscopy for long-standing colitis - a specialist commissioned pathway in accredited units.

  6. 06

    Deciding

    Cross-sectional imaging if acute

    CT for suspected toxic megacolon, perforation or intra-abdominal abscess - urgent, hospital-based.

  7. 07

    Deciding

    IBD MDT referral

    Discussion at a specialist commissioned IBD centre - Oxford, St Mark's, Cambridge and equivalent tertiary units.

Typical pathway: assessment and imaging within days, MDT plan within a fortnight in most UK IBD services.

Complications

What IBD complications actually look like.

The problems most often seen in day-to-day IBD care - and the features that mean it is time to escalate.

  • Strictures

    Fibrostenotic narrowing in the ileum or colon - cramping, bloating and vomiting after meals. Balloon dilation or resection.

  • Fistulae

    Perianal, entero-enteric, entero-cutaneous or rectovaginal tracts - specialist commissioned combined medical and surgical care.

  • Abscesses

    Intra-abdominal or perianal collections - imaging, drainage and antibiotics before immunosuppression is safe.

  • Toxic megacolon

    A life-threatening dilatation of the colon in severe colitis - emergency admission, surgery and specialist commissioned care.

  • Colorectal dysplasia and cancer

    Long-standing colitis raises colorectal cancer risk - chromoendoscopy surveillance in specialist commissioned units.

  • Short-bowel syndrome

    After extensive small-bowel resection - diarrhoea, malabsorption and dependence on nutritional support.

  • Extra-intestinal manifestations

    Arthropathy, uveitis, erythema nodosum, pyoderma gangrenosum and PSC - often mirror bowel activity.

  • Red flag - systemic sepsis

    Fever, tachycardia and abdominal pain in an IBD patient - assume abscess or perforation until proven otherwise.

Management

How IBD complications are managed in the UK.

Endoscopic and surgical options for structural problems, advanced medical therapy to keep the disease quiet, and coordinated care for the extra-intestinal side.

  • Endoscopic balloon dilation

    For short, fibrotic strictures without active inflammation - performed in specialist commissioned endoscopy units.

  • Bowel resection

    For non-dilatable strictures, complicated Crohn's or refractory colitis - colorectal surgery within an IBD MDT.

  • Perianal fistula care

    MRI mapping, examination under anaesthesia and seton drainage combined with biologic therapy - specialist commissioned pathway.

  • Advanced biologics

    Anti-TNF, ustekinumab, vedolizumab and risankizumab for moderate-to-severe disease - reduces complications when used early.

  • JAK inhibitors

    Upadacitinib and tofacitinib for selected refractory patients - close monitoring for infection, VTE and lipids.

  • Nutritional support

    Iron infusions, B12 replacement, calcium, vitamin D and, in short-bowel syndrome, parenteral nutrition and teduglutide.

  • Dysplasia surveillance

    Chromoendoscopy at set intervals based on disease duration, extent and PSC status - specialist commissioned service.

  • Coordinated MDT input

    Rheumatology, dermatology, ophthalmology and hepatology work alongside the IBD team - specialist commissioned care for each domain.

What this guide is based on

The sources behind every claim on this page.

UK and European specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your IBD team knows your history, imaging and past therapies. If in doubt, contact them - most services have a nurse helpline for exactly this.

  • British Society of Gastroenterology (BSG). Guidelines on the management of inflammatory bowel disease in adults.

  • European Crohn's and Colitis Organisation (ECCO). Consensus guidelines on Crohn's disease and ulcerative colitis.

  • NICE. Ulcerative colitis: management (NG130); Crohn's disease: management (NG129).

  • IBD UK Standards. Quality of care in inflammatory bowel disease.

  • Crohn's and Colitis UK. Patient information and complications resources.

Red flags

When IBD needs urgent attention.

Most flares are managed as outpatients. These are the signs that mean same-day contact with your IBD team or the emergency department.

  • Toxic megacolon

    Colonic dilatation over 6 cm with systemic toxicity - immediate hospital admission, IV therapy and urgent surgical review.

  • Perforation and peritonitis

    Sudden severe pain, guarding and shock in a known IBD patient - a surgical emergency.

  • Intra-abdominal abscess

    Fever, mass or worsening pain - urgent imaging and drainage before any immunosuppression is escalated.

  • Severe bloody diarrhoea

    More than six bloody stools a day with systemic upset meets Truelove and Witts criteria for severe colitis - admit and treat.

  • New jaundice or pruritus

    Consider primary sclerosing cholangitis, drug-induced liver injury or biliary complications - refer to hepatology.

  • New neurological or visual symptoms

    Painful red eye may be uveitis or scleritis; new neurology on biologics warrants specialist review.

  • Unexplained weight loss and anaemia

    Consider dysplasia, malignancy or malabsorption - endoscopy and cross-sectional imaging as appropriate.

  • Fever on immunosuppression

    Assume opportunistic infection - C. difficile, CMV and TB reactivation all warrant testing before escalating therapy.

  • Post-operative deterioration

    Rising CRP, ileus or drain output after IBD surgery - imaging for anastomotic leak or collection.

Living with it

A long-term condition, with a clear plan.

Four things make the biggest difference between flares and complications - self-monitoring, early contact, up-to-date preventive care and good peer support.

A quiet reminder

Early contact beats late admission, every time.

A phone call in the first week of a flare often prevents an admission in the second.

  1. 01 Monitor

    Know your normal

    Track stool frequency, bleeding, pain and energy. A shift from your usual pattern is the earliest warning of a complication.

  2. 02 Escalate

    Contact your IBD team early

    Most UK centres have an IBD nurse helpline. Ring at the first flare - waiting rarely helps and often costs a hospital stay.

  3. 03 Prevent

    Keep vaccinations and screens up to date

    Flu, pneumococcus and shingles matter more on immunosuppression. Cervical screening and skin checks are part of the plan.

  4. 04 Support

    Use Crohn's and Colitis UK

    Peer support, benefits advice and up-to-date information - a genuine complement to specialist care.

Frequently asked

Everything we get asked about IBD complications.

Quick answers on strictures, fistulae, cancer risk, medication safety and surveillance.

  • What are the most serious complications of IBD?

    Toxic megacolon, perforation, intra-abdominal abscess and severe haemorrhage are the acute emergencies. Longer term, fibrotic strictures, fistulating disease, colorectal cancer in long-standing colitis and short-bowel syndrome after multiple resections are the complications that most change life. Extra-intestinal problems - joints, skin, eyes and liver - are common and sometimes disabling in their own right.

  • Do IBD medications raise the risk of cancer?

    The overall excess risk is small but real. Thiopurines are associated with a modest rise in lymphoma and non-melanoma skin cancer. Long-term colitis itself carries a higher colorectal cancer risk, which is why chromoendoscopy surveillance in specialist commissioned centres matters. Biologics and JAK inhibitors have specific screening and monitoring pathways.

  • How often should I have colonoscopy for dysplasia surveillance?

    Intervals depend on disease duration, extent, PSC status and any past dysplasia. In UK practice, surveillance usually starts eight years after symptom onset for extensive colitis, with intervals of one, three or five years thereafter. It should be done in a specialist commissioned unit using high-definition colonoscopy with chromoendoscopy or equivalent.

  • Is perianal Crohn's treated differently?

    Yes. Perianal disease needs pelvic MRI, examination under anaesthesia and seton drainage combined with anti-TNF therapy from an early stage. Care sits within a specialist commissioned IBD MDT - gastroenterology, colorectal surgery and radiology working together.

  • What is short-bowel syndrome?

    A malabsorptive state after extensive small-bowel resection - typically less than 200 cm of functioning bowel. Features include high-volume diarrhoea, dehydration, weight loss and vitamin and mineral deficiencies. Management involves specialist nutrition teams and sometimes long-term parenteral support or GLP-2 analogues.

  • How is TB reactivation prevented before starting a biologic?

    A screening pathway with interferon-gamma release assay, chest X-ray and risk-factor review is completed before any anti-TNF or JAK inhibitor is started. Latent TB is treated with chemoprophylaxis before advanced therapy begins - a specialist commissioned pathway within the IBD service.

Related content

Keep reading.

Pulse Healthcare concierge

Send us your enquiry

A concierge service for UK private healthcare. We match you with the best vetted clinics and consultants in our network - they then contact you directly.

So we can match you to the right clinician close to you.

We reply to every enquiry within 24 hours (Mon–Fri). Confidential - your details are never shared outside our vetted consultant network.