Collagenous colitis

Overview
Collagenous colitis is an inflammatory colonic disease with peak incidence in the 5th decade of life, affecting women more than men. Its clinical presentation involves watery diarrhea, usually in the absence of rectal bleeding. It is often classified under the umbrella entity microscopic colitis, along with a related condition, lymphocytic colitis.

Diagnosis
On colonoscopy, the mucosa of the colon typically looks normal, but biopsies of affected tissue usually show deposition of collagen in the lamina propria, which is the area of connective tissue between colonic glands. Radiological tests, including barium enemas are typically normal.

Treatment
Treatment of collagenous colitis is often challenging, and many agents have been used therapeutically:


 * Bismuth agents, including Pepto-Bismol
 * 5-aminosalicylic acid
 * Budesonide
 * Immunosuppressants, including azathioprine
 * Corticosteroids

Disease associations
An association between collagenous colitis and celiac disease has been reported, but there is no evidence that dietary restrictions used in celiac disease management are of benefit in collagenous colitis therapy.

There have also been reports of an association between collagenous colitis and lymphoma.