Unusual Reaction to Chlorambucil in a Patient With Chronic Lymphocytic Leukemia

A severe skin hypersensitivity reaction to chlorambucil occurred in a 62-year-old woman. Patch testing showed a delayed type of hypersensitivity to chlorambucil. Serum precipitin tests were negative and an immediate type of scratch-test response was also negative. Although rare, allergy to chlorambucil should be considered in the differential diagnosis of patients presenting with allergic symptoms or rash while receiving therapy with this alkylating agent.