Bullous eruption and elevated leukocyte alkaline phosphatase in the course of busulfan-treated chronic granulocytic leukemia.

IHRONIC GRANULOCYTIC LEUKEMIA is characterized by hepatosplenomegaly, a markedly elevated white blood cell count with a spectrum of immature and mature granulocytic elements present, a proliferative granulocytic bone marrow, low levels or absence of leukocyte alkaline phosphatase activity and the presence of the Philadelphia chromosome.’ The patient to be described had chronic granulocytic leukemia and developed an erythema multiforme like rash following busulfan therapy. The leukocyte alkaline phosphatase activity at the height of the rash was markedly increased in association with a normal white blood cell count. The serum vitamin B12 and B52 binding capacity were significantly elevated at this time. Tile leukocyte alkaline phosphatase activity fell gradually to zero and the white blood cell count increased as the rash subsided. The B12 levels remained elevated.