Definition and diagnosis of microscopic and collagenous colitis in adults
Microscopic colitis is defined by the presence of lymphocytic infiltrates without architectural distortion. If there is a prominent subepithelial collagen band, then it is called collagenous colitis.
Patients with microscopic colitis and collagenous colitis often present with chronic diarrhoeaNguyen, 2016. Diagnosis is made if typical features are seen on histological investigation of biopsies obtained during colonoscopyNguyen, 2016.
Microscopic colitis and collagenous colitis are more common in females than males, and prevalence increases with ageNguyen, 2016. The aetiology remains unclear, although there is an association with certain classes of medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), proton pump inhibitors (PPIs) and selective serotonin reuptake inhibitors (SSRIs).