Objective: Data on collagenous colitis (CC) and lymphocytic colitis (LC) have been based on retrospective studies of registries of patients from multiple hospitals. Such studies may induce a selection of patients with severe forms of the disease, and conclusions about the clinical spectrum of the disease and treatment efficacy are difficult to be drawn. The aim of this study was to compare the clinical features, response to treatment, and long-term follow-up of CC and LC in a large group of patients prospectively diagnosed in a single center.
Methods: A specific program was undertaken to prospectively diagnose all patients with microscopic colitis from those referred for a full colonoscopy because of recurrent or chronic diarrhea. Detailed clinical and histological features, response to treatment, and long-term follow-up were compared in patients with confirmed CC and LC.
Results: Thirty-seven patients with CC and 44 with LC were included. Patients with CC were significantly younger and had a significantly longer duration of diarrhea before diagnosis than those with LC. Otherwise, clinical presentation was similar. Drug-induced disease was suspected for ticlopidine, flutamide, gold salts, and bentazepam in LC. Complete resolution of diarrhea was achieved in all patients, spontaneously occurring in nearly 20% of them. Response to salicylates (mainly, mesalazine) was significantly better in LC than in CC (86% vs 42%, p = 0.005). Cholestyramine was highly effective in patients of both groups with concomitant bile acid malabsorption. Patients with CC required prednisone more often than those with LC (30% vs 4.5%, p = 0.005). Both prednisone and budesonide controlled ileal release were highly effective in patients with CC (82% and 89% efficacy). After cessation of diarrhea, 25% of patients with LC and 30% of those with CC relapsed after a mean follow-up of around 3 yr.
Conclusions: CC and LC share a similar clinical picture and have a benign course with long-term cessation of diarrhea in more than 70% of patients. Mesalazine and budesonide seem to be good options as first-line treatment in LC and CC, respectively. Cholestyramine may be a good alternative in patients with concomitant bile acid malabsorption.