Azathioprine-Induced Severe Bone Marrow Toxicity-A Report of 3 Cases

Abstract

Dermatologists have been using azathioprine as a ”steroid sparing agent” for the treatment of various dermatoses including photodermatoses, immunobullous diseases, psoriasis and eczematous diseases. However, in Taiwan, the currently approved indications of azathioprine include only adjunct therapy of renal transplant, systemic lupus erythematosus, severe rheumatoid arthritis, and leukemia. Owing to the off-label nature of azathiopine use in most dermatological practice, clinical vigilance must be taken. We herein report 3 cases of severe bone marrow toxicity after the use of azathioprine and discuss the pathogenesis and suggestive management of this rare complication. The first patient had prolonged pancytopenia lasting for 3 months despite immediate azathioprine withdrawal and 2 consecutive doses of granulocyte colony-stimulating factor. The full blood count of the other two patients had returned to normal one week after treatment. The result of genotyping of three patients to detect most prevalent mutant allele (TPMT(superscript *)3C) was negative.