[Safety of azathioprine therapy adjusted to thiopurine methyltransferase activity in the treatment of infantile atopic dermatitis. Report on 7 cases].

BACKGROUND In a small number of cases of childhood atopic dermatitis, topical therapy is ineffective, necessitating prolonged use of systemic immunosuppressants. Over the last few years, a better understanding of the metabolic pathways involved in azathioprine breakdown has enabled us to use this drug more safely. In this study, we evaluated the toxicity of azathioprine treatment adjusted to thiopurine methyltransferase activity in children with severe atopic dermatitis. MATERIAL AND METHODS We performed a retrospective study of the side effects of azathioprine therapy adjusted to thiopurine methyltransferase activity in children aged under 14 years with atopic dermatitis who were treated in the dermatology department of Hospital Universitario Insular de Gran Canaria in Gran Canaria, Spain. Side effects were evaluated by analysis of leukocyte count and transaminase levels at baseline, after 1 month of treatment, and every 3 months thereafter. RESULTS During the last 4 years, 7 children (mean age, 10 years) with severe atopic dermatitis received azathioprine in our department. Mean duration of treatment was 12 months (range, 1 to 38 months). Only 2 patients presented mild transient leukopenia that did not require treatment to be suspended. DISCUSSION Our experience shows that, when adjusted to thiopurine methyltransferase activity, azathioprine is a safe drug for the treatment of children with severe atopic dermatitis. However, clinical trials should be performed to compare the risk-benefit ratios of the different immunosuppressants used to treat these patients.