Clostridium difficile toxin assay in psoriatic patients.

Chemotherapy-induced pseudomembranous colitis is most commonly associated with methotrexate and 5-fluorouracil. Methotrexate and mesalazine have also been used for the treatment of psoriasis but the effect of these therapies on the Clostridium difficile carriage in the stool of psoriatic patients has not been studied. Our aim was to detect the presence of C. difficile toxin in patients with psoriasis hospitalized for systemic therapy and in those receiving methotrexate and mesalazine. A total of 58 patients with psoriasis were divided into three groups: group A comprised 30 patients admitted with psoriasis involving >30% body surface area, group B1 comprised 15, psoriatic patients receiving methotrexate (0.3-0.4 mg/kg/week), group B2 included 6 patients receiving mesalazine (50-60 mg/kg/day) while group C comprised of 7 patients (5 on methotrexate, 2 on mesalazine) in whom stool samples were taken twice. Among patients in groups B1 and B2, stool samples were taken after at least 4 weeks of therapy. Detection of C. difficile toxin in stool samples was done using the latex agglutination method. Out of the 58 patients 47 were males and 11 were females. The mean age of the patients was 45+/-2.5 years and the duration of the disease was 3+/-0.9 years. Positive C. difficile toxin was found in a total of 19 patients in all three groups (5 patients in group A, 9 in group B1, 2 in group B2 and 3 in group C). Three patients complained of slight abdominal discomfort and increased frequency of stool, of whom 2 had toxin positive in low titres. The rest of the 17 patients who were positive for C. difficile toxin were asymptomatic. There is a obvious rise in the rate of GIT carriage of C. difficile to a variable degree in patients on methotrexate and mesalazine. However, no clear correlation of the gastrointestinal symptoms with either the presence of toxin or its titre could be established.