Non-IBD colitides (eosinophilic, microscopic).

Microscopic colitis includes the terms lymphocytic colitis and collagenous colitis, and is a common cause of chronic diarrhoea in older adults. The incidence of microscopic colitis has increased over time and has reached levels comparable to other forms of inflammatory bowel disease. In this chapter, an updated review on the epidemiology, diagnosis and treatment of microscopic colitis has been provided. There is limited data available about eosinophilic colitis, which is the least common of the eosinophilic GI disorders. It is important to rule out the secondary causes of colonic eosinophilia in patients with suspected eosinophilic colitis.