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This supplement has been commissioned and funded by Ferring Pharmaceuticals and developed in partnership with Guidelines in Practice. See below for full disclaimer.

Information for UK healthcare professionals only. 

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Dr Kevin Barrett, GP Partner, New Road Surgery; Clinical Director, The Grand Union PCN; Chair, Primary Care Society for Gastroenterology; Vice‑Chair, Watford & Three Rivers Locality HVCCG


Inflammatory bowel disease (IBD) is a term used to describe a group of conditions that involve inflammation of the gastrointestinal tract. They include ulcerative colitis (term first used in 1888) and Crohn’s disease (first described in 1932),1 as well as microscopic colitis. This article covers the identification and primary care management of ulcerative colitis and microscopic colitis in adults, as both conditions are much less common in children.

Most cases of ulcerative colitis present to primary care in a straightforward manner, but it can sometimes take longer than normal to suspect, investigate, refer, and diagnose. Microscopic colitis is less common and this condition is often overlooked, making it even harder for a diagnosis and effective therapy to be initiated.

Ulcerative colitis

Ulcerative colitis has a prevalence of around 432 per 100,000,2 with a peak incidence occurring from late adolescence to early adulthood, and some studies showing a small second peak in the fifth decade.3

Typical symptoms include diarrhoea, often with visible blood, weight loss, and malaise. Abdominal pain may be present but is not a universal feature. Extraintestinal symptoms include joint aches, lethargy (unrelated to anaemia), skin problems (erythema nodosum or pyoderma gangrenosum), liver disease (primary sclerosing cholangitis), and ocular complications. Sometimes the extraintestinal symptoms are the main presenting complaint and the gastrointestinal symptoms are a lesser concern to the patient.

One key discriminator for structural bowel disease compared to functional bowel disease is the presence of nocturnal symptoms; patients with Irritable Bowel Syndrome (IBS) almost always have an undisturbed night’s sleep, but those with all forms of IBD or colorectal cancer are far more likely to suffer from urgency and the need to open their bowels overnight or risk incontinence with the consequent disruption to sleep patterns, social and work activities, and relationships.


Figure 1 shows a typical investigation and referral pathway.4 Once red flag symptoms have been considered and dealt with (usually with a suspected cancer referral pathway) it is important to carry out a face-to-face examination to look for abdominal masses, jaundice, and anaemia. A rectal examination is recommended as the presence of a rectal mass would change the urgency of referral.

Inflammatory causes should be excluded with a full blood count and a C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) test.5 Coeliac disease should be excluded with an IgA tissue transglutaminase (tTG) antibody serology test, assuming the patient has been consuming some gluten in more than one meal every day for at least 6 weeks before testing.5

In adults with normal blood investigations but whose symptoms persist, a faecal calprotectin is the next recommended test. If faecal calprotectin is over 100 mcg/g then there is a reasonable probability that structural bowel disease is present, and the higher the result the greater that probability. Local systems will have different thresholds for referral or for re-testing, so familiarise yourselves with these. If IBD is suspected then it should be made clear on the referral as the IBD Standards recommend that patients are seen within 4 weeks of referral,6 although only 21% of adult IBD units achieved this in 2019.7

Figure 1_V.2

Management in primary care

The diagnosis and treatment of ulcerative colitis is always conducted under the supervision of secondary care, and ongoing biological immunosuppressive therapy remains the remit of specialists. Many patients with mild-to-moderate symptoms will be under shared care agreements and those with mild or transient symptoms may be discharged once initial treatment has proven effective. It is up to primary care to manage ongoing prescriptions for oral and rectal medications (sometimes with shared care agreements) and to provide support for some of the associated issues such as fatigue, contraception, and employment or study.

It is important to encourage compliance with medication as patients who are non-adherent to oral mesalazines have a five times increased risk of flares compared to those who continue to take them,8 and regular mesalazine therapy reduces the risk of colorectal cancer by 75%.9 The dose of mesalazines used for maintenance is lower than that used for initial treatment and flare management, and maintenance treatment can be given as a once-daily dose to aid compliance.

Case study 1 part 1

Flare management

The 2019 IBD Standards state that every patient should have an individualised care plan that contains a strategy for properly identifying and managing a flare.6 For the majority of patients that do not have this, it is advisable to contact the local IBD advice line, details of which can be found on the interactive map produced by Crohn’s & Colitis UK: https://crohnsandcolitis.org.uk/support/find-an-ibd-nurse-specialist

As part of the RCGP and Crohn’s & Colitis UK IBD Spotlight Project that ran from 2017 to 2020, a pair of flowcharts were produced to help guide clinicians treating suspected flares of Ulcerative Colitis and Crohn’s Disease and the latest versions can be found at: www.rcgp.org.uk/ibd

The treatment of flares depends on the location of the disease. According to the latest guidance from NICE and the British Society of Gastroenterology, patients with anything other than very distal disease should have oral as well as rectal treatment.3,10 Steroids should be avoided where possible, but there is a place for oral budesonide in inducing remission in ulcerative colitis due to the reduced systemic effects compared with prednisolone.11 Different formulations are available and prescribing by brand is often appropriate to ensure that the correct preparation is given to the patient. The choice of preparation could also be based on the location of disease and approved indication.12 For mild-to-moderate ulcerative colitis flare management, only one oral budesonide is licenced, which is budesonide MMX. It is important to remember that standard budesonide formulations are predominantly released earlier in the gastrointestinal tract, whereas budesonide MMX is released throughout the whole colon.11 

Case study 1 part 2_V.2


  • Ulcerative Colitis has both gastrointestinal and extraintestinal symptoms
  • Patients typically have chronic diarrhoea, often blood in the stool, and nocturnal symptoms
  • Clinical examination is important, and blood tests for inflammation should be conducted
  • Diagnosis can only be made at endoscopy; faecal calprotectin can be used as a guide to assess the need for and urgency of referral
  • Long-term adherence to mesalazine treatment reduces the risk of flares and of colorectal cancer.

Microscopic colitis

Irritable bowel syndrome (IBS) affects 10–20% of the population13 but other conditions (microscopic colitis, bile acid diarrhoea, and dyssynergic defaecation) have similar symptoms (see Table 1).5 Microscopic colitis is a cause of chronic, non-bloody, watery diarrhoea,14 particularly in older patients in whom the impact on quality of life can be significant. Microscopic colitis has an incidence of 11.4 per 100,000 person-years but a prevalence of 119 per 100,000 population which reflects the chronicity of the condition.14 It is found in 12.8% of those with unexplained chronic watery diarrhoea.14 The rate of diagnosis is increasing in Westernised countries.14 The median age at diagnosis is 60, reflecting an older population than those typically diagnosed with other types of inflammatory bowel disease, although 25% are aged under 45 years.14 Risk factors include the presence of another autoimmune condition, symptoms being present for longer than 12 months, female sex, smoking, and the long-term use of proton-pump inhibitors, non-steroidal anti-inflammatory drugs, and selective serotonin reuptake inhibitors, although a causal relationship has not been established.5,14

Table 1

There are two histological subtypes, collagenous colitis (CC) and lymphocytic colitis (LC).14 Both are characterised by the presence of an inflammatory infiltrate in the lamina propria, but differentiated by having either a thickened collagen band (CC) or an increased amount of intraepithelial lymphocytes (LC).14 The differentiation between these does not affect the diagnosis or management, particularly from a primary care perspective.


The most common symptom in microscopic colitis is chronic watery, non-bloody diarrhoea, frequently associated with faecal urgency, the need to open the bowels at night, and faecal incontinence.14 Cramping abdominal pain may be present, and some patients may lose weight.14 These symptoms can be severe enough to make patients effectively housebound and impact their ability to maintain relationships and employment. Patients may meet the criteria for an urgent cancer pathway referral,16 however the endoscopic appearance of the bowel mucosa is typically normal. Around 5% of patients with normal colonoscopy findings have microscopic colitis subsequently confirmed on histology from biopsies.17

Case study 2 part 1


Microscopic colitis cannot be diagnosed in primary care. Patients will have a normal abdominal examination and a normal rectal examination. A number of initial investigations are required in line with NICE CG61.13 It is important to consider red flag symptoms that may indicate an underlying colorectal or ovarian cancer and refer or investigate appropriately. Patients may be referred on a suspected colorectal cancer pathway, receive a colonoscopy without biopsies or a computed tomography (CT) colonoscopy, and be discharged back to primary care. This may lead to patients being falsely reassured that there is no structural pathology present, but if patients do not respond to the normal therapies for IBS, particularly diarrhoea-predominant IBS (IBS-D) that include advice on fibre intake and physical exercise, as well as pharmacological therapies, it is worth re-referring them to gastroenterology for consideration of biopsies if these have not been done at a previous colonoscopy.18 Biopsies can be called out as the gold standard of diagnosis. 

Inflammatory causes should be excluded with a full blood count and a CRP or ESR, and coeliac disease with a tTG antibody serology test, assuming the patient has been consuming some gluten in more than one meal every day for at least 6 weeks before testing.5,19 Coeliac disease is present in 3–4% of patients with microscopic colitis,14 reflecting an overlap with other autoimmune conditions.

A faecal calprotectin test can be a useful additional test in adults with normal investigations but whose symptoms persist. If faecal calprotectin is under 100 mcg/g then IBS is the likely diagnosis in 98% of this group of patients, and this increases slightly to 99% if the patient is aged under 50 and the calprotectin result is under 50 mcg/g.4 (See Figure 1.)

NICE CG61 states that the following tests are not necessary to confirm a diagnosis of IBS in adults: ultrasound, rigid/flexible sigmoidoscopy, colonoscopy, barium enema, thyroid function test, faecal ova and parasite test, faecal occult blood, hydrogen breath test (for lactose intolerance and bacterial overgrowth), but these tests may be considered in patients not responding to initial advice and therapies.13

Case study 2 part 2_V.2


The initial treatment for most patients with microscopic colitis is oral budesonide at a dose of 9 mg/day for a period of 6–8 weeks. In clinical studies, 81–84% of patients responded to this treatment compared to 36–43% given a placebo.14  Patients may enter and stay in remission at this point, however some studies have shown that patients may need long-term budesonide (for at least 6 months) at 3 mg or 6 mg/day;14  this should be titrated according to clinical response. Prednisolone, loperamide, bismuth, mesalazines, antibiotics, or probiotics have been tried as treatments but are not recommended,14  although some patients may find a degree of symptomatic relief with loperamide or probiotics. Thiopurines or biologics may sometimes be used to treat patients who do not respond to budesonide but this will need a specialist opinion.14


  • Microscopic colitis is a subset of inflammatory bowel disease and has two histological subtypes
  • Patients typically have chronic, watery diarrhoea, often with urgency, incontinence and nocturnal symptoms
  • Clinical examination, blood tests and faecal calprotectin tests are usually normal
  • The bowel mucosa usually appears normal; biopsies are needed for a histological diagnosis
  • First-line treatment is with oral budesonide 9 mg/day for an initial period of 6–8 weeks.


  1. Baron J. Inflammatory bowel disease up to 1932. Mt Sinai J Med 2000; 67 (3): 174–189.
  2. Jones G-R, Lyons M, Plevris N et al. IBD prevalence in Lothian, Scotland, derived by capture-recapture methodology. Gut 2019; 68 (11): 1953–1960.
  3. NICE. Ulcerative colitis: management. NICE Guideline 130. NICE, 2019. Available at: www.nice.org.uk/NG130
  4. NICE. Faecal calprotectin diagnostic tests for inflammatory diseases of the bowel. Diagnostics Guidance 11. NICE,2013. Available at: www.nice.org.uk/DG11
  5. Vasant D, Paine P, Black C et al. British Society of Gastroenterology guidelines on the management of irritable bowel syndrome. Gut 2021; 70 (7): 1214 LP – 1240. Available at: gut.bmj.com/content/70/7/1214.abstract
  6. IBD UK. IBD Standards. www.ibduk.org/ibd-standards (accessed on 12 November 2021).
  7. Kapasi R, Glatter J, Winsor G et al. O18 IBD care in 2020: results from the first IBD UK patient and service benchmarking tool. Gut 2021; 70: A10. Available at: gut.bmj.com/content/70/Suppl_1/A10.1.abstract
  8. Kane S, Huo D, Aikens J, Hanauer S. Medication nonadherence and the outcomes of patients with quiescent ulcerative colitis. Am J Med 2003; 114 (1): 39–43. 
  9. Eaden J, Abrams K, Ekbom A, Jackson E et al. Colorectal cancer prevention in ulcerative colitis: a case-control study. Aliment Pharmacol Ther 2000; 14 (2): 145–153. 
  10. Lamb C, Kennedy N, Raine T et al. British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults. Gut 2019; 68: s1–106. 
  11. Abdalla M, Herfarth H, Budesonide for the treatment of ulcerative colitis. Expert Opinion on Pharmacotherapy 2016; 17 (11): 1549–1559.
  12. Miehlke S, Acosta M, Bouma G et al. Oral budesonide in gastrointestinal and liver disease: A practical guide for the clinician. Journal of Gastroenterology and Hepatology 2018; 33: 1574–1581.
  13. NICE. Irritable bowel syndrome in adults: diagnosis and management. Clinical Guideline 61. NICE, 2008 (last updated April 2017). Available at: www.nice.org.uk/CG61
  14. Miehlke S, Guagnozzi D, Zabana Y et al. European guidelines on microscopic colitis: United European Gastroenterology (UEG) and European Microscopic Colitis Group (EMCG) statements and recommendations. United European Gastroenterol J 2021; 9: 13–37. Available at: doi.org/10.1177/2050640620951905
  15. Münch A, Sanders D, Molloy-Bland M et al. Undiagnosed microscopic colitis: a hidden cause of chronic diarrhoea and a frequently missed treatment opportunity. Frontline Gastroenterology 2020; 11: 228–234.
  16. NICE. Suspected cancer: recognition and referral. NICE Guideline 12. NICE, 2015 (last updated January 2021). Available at: www.nice.org.uk/ng12
  17. Haq M, Shah S. PWE-065 colonoscopy and biopsy practice in patients with diarrhoea. Gut 2013; 62: A157. Available at: gut.bmj.com/content/62/Suppl_1/A157.1.abstract
  18. Rees C, Thomas Gibson S, Rutter M et al. UK key performance indicators and quality assurance standards for colonoscopy. Gut 2016; 65: 1923–1929. Available at: gut.bmj.com/content/65/12/1923.abstract
  19. NICE. Coeliac disease: recognition, assessment and management. NICE Guideline 20. NICE, 2015. Available at: www.nice.org.uk/ng20

This supplement has been commissioned and funded by Ferring Pharmaceuticals and developed in partnership with Guidelines in Practice. Ferring suggested the topic and author, and carried out full medical approval on all materials to ensure compliance with regulations. The author was paid an honorarium. The views and opinions of the author are not necessarily those of Guidelines in Practice, its publisher, advisers, or advertisers. No part of this publication may be reproduced in any form without the permission of the publisher.


Date of preparation: December 2021