Seasonal pattern of onset in lymphocytic colitis.

Background: The etiology of lymphocytic colitis, a microscopic colitis syndrome, has remained elusive. Because 1) many infectious enteritides exhibit seasonal variability in incidence and 2) a few investigators have proposed some infectious mechanism in lymphocytic colitis, our aim was to determine if any variability in symptom onset existed among lymphocytic colitis patients diagnosed at our institution.

Study: We identified 71 nonduplicated, consecutive patients with lymphocytic colitis over a 4-year period using rigorous clinicopathologic inclusion criteria: 1) chronic watery diarrhea, 2) endoscopically normal colon, 3) no evidence for celiac sprue or drug-induced colitis, 4) diffuse colitis with increased intraepithelial lymphocytes of at least 10 lymphocytes per 100 epithelial cells, 5) evidence of surface epithelial damage, and 6) no significant neutrophilic infiltrates, architectural distortion of the mucosa, or subepithelial collagen deposits.