Cutaneous reactions in hairy cell leukaemia treated with 2-chlorodeoxyadenosine and allopurinol.

The purine nucleoside analogue 2-chlorodeoxyadenosine (2-CdA) is currently considered by many as first-line therapy for hairy cell leukaemia. Cutaneous reactions have occasionally been reported with this drug, particularly if used with allopurinol. We report a high frequency of skin reactions in 15 consecutive patients with hairy cell leukaemia treated with 17 courses of 2-CdA. These reactions occurred only in those receiving allopurinol and, in two patients, were severe enough to warrant steroid therapy. The routine concomitant use of allopurinol is therefore not recommended in this setting.