Leukemoid reaction in erythema nodosum leprosum in a leprosy patient.

A case of lepromatous leprosy with erythema nodosum leprosum (ENL) presenting as a myeloid leukemoid reaction is reported. Very high leucocyte count with immaturity of the cells in myeloid series was present in peripheral blood. High leucocyte alkaline phosphatase score, absence of hepatosplenomegaly and transient nature of leukemoid reaction differentiated it from chronic myeloid leukemia and acute myeloblastic leukemia. The possible mechanisms of leukemoid reaction in ENL are discussed.