Lymphocytic Colitis

Lymphocytic colitis is the subtype of microscopic colitis with increased intraepithelial lymphocytes but no thickened collagen band.

• Histology: over 20 intraepithelial lymphocytes per 100 surface epithelial cells, increased lamina propria cellularity, intact surface architecture, no thickened collagen.
• Incidence is similar to collagenous colitis, with a smaller female predominance (about 2:1), and presents at a slightly younger age.
• Stronger association with celiac disease, so celiac serology is essential.
• Triggers include NSAIDs, PPIs, SSRIs, and infection.
• May evolve into collagenous colitis in a few patients.

• Chronic watery diarrhoea, urgency, nocturnal stools, abdominal pain, weight loss, bloating.
• Intermittent course with spontaneous remission in many.
• Coexisting autoimmune disease or celiac disease should be sought.
• Differential diagnosis includes celiac disease, irritable bowel syndrome, bile acid diarrhoea, and infection.

• Colonoscopy usually looks normal. Multiple biopsies from the right and left colon are required.
• Histology confirms increased intraepithelial lymphocytes with preserved crypt architecture. Distinguish from Crohn disease, celiac disease, and drug induced changes.
• Celiac serology (tTG IgA with total IgA) and duodenal biopsies if positive, because the lymphocytic pattern is frequently celiac related.
• Stool microbiology, thyroid function, and medication review.

• Review and stop causative drugs (NSAIDs, PPIs, SSRIs).
• Treat coexisting celiac disease with a gluten free diet.
• Budesonide 9 mg daily for 6 to 8 weeks, then taper, with remission in about 80%.
• Maintenance budesonide 3 to 6 mg daily for relapse prone patients.
• Mild disease: loperamide 2 to 4 mg up to four times daily, bismuth subsalicylate 262 mg three times daily, or cholestyramine 4 g daily if bile acid diarrhoea.
• Refractory: azathioprine 2 mg/kg, methotrexate, anti TNF or vedolizumab.
• Annual review. Prognosis is good and malignancy risk is not increased.