Red Flags
- Severe acute UC (Truelove-Witts: ≥6 bloody stools/day plus systemic toxicity) — admit; IV methylprednisolone; rescue with infliximab or ciclosporin if no response by day 3; surgical review[1]
- Toxic megacolon — fever, tachycardia, abdominal distension, colon ≥6 cm — emergency surgical review; risk of perforation[1]
- Crohn's perforation, abscess, obstruction — surgical emergency; CT abdomen, IV antibiotics, drainage or resection[1]
- Active IBD with HBV/TB/strongyloides exposure before biologics — screen and treat latent infection; reactivation risk on TNF inhibitors[1]
First-line treatment
Interventions
- Surgical management[1]UC: total colectomy + ileal pouch-anal anastomosis for refractory disease, dysplasia, or cancer. Crohn's: limited resection for stricturing, fistulising, or refractory disease (recurrence is common; preserve bowel)
- Vaccination and infection screening pre-biologic[1]Screen HBV, HCV, HIV, latent TB (IGRA + CXR), Strongyloides in endemic settings; vaccinate against influenza, pneumococcal, HPV, hepatitis B, varicella before immunosuppression
First-line drug therapy
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Mesalazine (5-ASA)[1] | Aminosalicylate | Mesalazine 2.4–4.8 g PO daily for induction; 2–3 g daily for maintenance; topical 1–4 g rectal for proctitis/distal disease | 50–100 mg/kg/day | First-line for mild-moderate UC; minimal role in Crohn's |
| Prednisolone (induction)[1] | Glucocorticoid | 40 mg PO once daily, taper over 8 weeks; IV methylprednisolone 60 mg daily for severe disease | 1–2 mg/kg/day | Induction only; not for maintenance — long-term toxicity; budesonide MMX for distal UC, ileal Crohn's |
| Azathioprine or 6-mercaptopurine[1] | Thiopurine immunomodulator | Azathioprine 2–2.5 mg/kg/day; 6-MP 1–1.5 mg/kg/day; check TPMT before starting | Same per kg | Steroid-sparing maintenance in moderate disease; combination with TNF inhibitor reduces immunogenicity |
| Infliximab[1] | Anti-TNF biologic | 5 mg/kg IV at 0, 2, 6 weeks then every 8 weeks; combination with immunomodulator preferred | Same per kg | Moderate-severe UC and Crohn's; rescue therapy in severe acute UC; pre-treatment HBV/TB/strongyloides screen |
| Vedolizumab or ustekinumab[1] | Gut-selective integrin / IL-12/23 inhibitor | Vedolizumab 300 mg IV at 0, 2, 6 weeks then q8w; ustekinumab 6 mg/kg IV induction then 90 mg SC q8w | — | Alternative biologics; vedolizumab gut-selective, less infection risk; ustekinumab effective in Crohn's |
| Tofacitinib or upadacitinib (UC)[1] | JAK inhibitor | Tofacitinib 10 mg PO BD induction × 8 weeks then 5 mg BD; upadacitinib 45 mg PO daily induction × 8 weeks then 15–30 mg daily | — | Moderate-severe UC; small-molecule oral; specialist; cardiovascular and thrombotic risk monitoring per ORAL Surveillance |
Mesalazine (5-ASA)[1]
Aminosalicylate
- Adult
- Mesalazine 2.4–4.8 g PO daily for induction; 2–3 g daily for maintenance; topical 1–4 g rectal for proctitis/distal disease
- Paediatric
- 50–100 mg/kg/day
First-line for mild-moderate UC; minimal role in Crohn's
Prednisolone (induction)[1]
Glucocorticoid
- Adult
- 40 mg PO once daily, taper over 8 weeks; IV methylprednisolone 60 mg daily for severe disease
- Paediatric
- 1–2 mg/kg/day
Induction only; not for maintenance — long-term toxicity; budesonide MMX for distal UC, ileal Crohn's
Azathioprine or 6-mercaptopurine[1]
Thiopurine immunomodulator
- Adult
- Azathioprine 2–2.5 mg/kg/day; 6-MP 1–1.5 mg/kg/day; check TPMT before starting
- Paediatric
- Same per kg
Steroid-sparing maintenance in moderate disease; combination with TNF inhibitor reduces immunogenicity
Infliximab[1]
Anti-TNF biologic
- Adult
- 5 mg/kg IV at 0, 2, 6 weeks then every 8 weeks; combination with immunomodulator preferred
- Paediatric
- Same per kg
Moderate-severe UC and Crohn's; rescue therapy in severe acute UC; pre-treatment HBV/TB/strongyloides screen
Vedolizumab or ustekinumab[1]
Gut-selective integrin / IL-12/23 inhibitor
- Adult
- Vedolizumab 300 mg IV at 0, 2, 6 weeks then q8w; ustekinumab 6 mg/kg IV induction then 90 mg SC q8w
- Paediatric
- —
Alternative biologics; vedolizumab gut-selective, less infection risk; ustekinumab effective in Crohn's
Tofacitinib or upadacitinib (UC)[1]
JAK inhibitor
- Adult
- Tofacitinib 10 mg PO BD induction × 8 weeks then 5 mg BD; upadacitinib 45 mg PO daily induction × 8 weeks then 15–30 mg daily
- Paediatric
- —
Moderate-severe UC; small-molecule oral; specialist; cardiovascular and thrombotic risk monitoring per ORAL Surveillance
Safety-net
- Take maintenance therapy daily even when symptom-free — flares prevention is the goal[1]
- New fever, severe abdominal pain, bloody diarrhoea increase, or weight loss — same-day medical review (flare or complication)[1]
- Inform any new clinician about your IBD therapy — biologics and JAK inhibitors increase infection risk; vaccinate before travel[1]
Referral criteria
- Severe acute UC or toxic megacolonEmergency department; gastroenterology and colorectal surgery same-day[1]
- Crohn's complication (perforation, abscess, obstruction)Surgical emergency; gastroenterology + colorectal surgery[1]
- Moderate-severe IBD failing 5-ASA + thiopurineGastroenterology / IBD service for biologic or JAK inhibitor[1]
- IBD with extraintestinal manifestation (uveitis, axial arthritis, PSC)Multidisciplinary IBD-specialist team[1]
Clinical summary
Diagnosis and treatment of ulcerative colitis and Crohn's disease per current ECCO/ACG guidance — biologics and small molecules in moderate-severe disease.