Prevalence of primary eosinophilic colitis in patients with chronic diarrhea and diarrhea-predominant irritable bowel syndrome.

INTRODUCTION: Primary eosinophilic colitis (PEC) is an inflammatory disease caused by the infiltration of eosinophils into the mucosa of the colon, determined after having ruled out other possible causes. It is characterized by abdominal pain and diarrhea and its prevalence is unknown.

AIMS: To know the prevalence of PEC in patients with chronic diarrhea and in those with clinical criteria for diarrhea-predominant irritable bowel syndrome (IBS-D).

PATIENTS AND METHODS: All patients with chronic noninflammatory diarrhea that were consecutively seen over a decade were studied through colonoscopy, with systematic biopsy. Patients with a known or decompensated organic disease, alarm features, abnormal minimal laboratory test results, and factors associated with eosinophilia were excluded. Patients with the clinical criteria for IBS-D (Rome III) were selected from the general group. Eosinophilic colitis was defined as the presence of>35eosinophils/100 epithelial cells per field in any of the segments.

RESULTS: From the 683 patients seen, a total of 545 patients (361 women) were included in the study. Twenty-two cases of PEC were detected, resulting in a prevalence of 4.0%. A total of 343 patients had IBS-D criteria (223 women), with 16 cases of PEC detected, for a prevalence of 4.7%. Colonoscopy was normal, or almost normal, in all the PEC cases detected.

CONCLUSIONS: The prevalence of PEC was 4.0% in the patients with chronic diarrhea and 4.7% in the patients with IBS-D. Peripheral eosinophilia appeared to be the main distinctive clinical characteristic, but systematic biopsy was essential for making the diagnosis.