Severe necrotizing cutaneous lesions complicating treatment with interferon beta-1b

To the Editor: Recombinant interferon beta-1b (Betaseron) was licensed in 1993 to reduce exacerbations of multiple sclerosis. Approval of the drug was greeted enthusiastically, despite a modest 30 percent reduction in relapses and side effects that include local inflammatory reactions and a flulike syndrome.¹ We report the occurrence of severe necrotizing cutaneous reactions in a 38-year-old woman with an eight-year history of multiple sclerosis. She self-injected the standard dose of recombinant interferon beta-1b (9 million units) subcutaneously on alternate days. Erythematous patches appeared at the injection sites on both thighs during the third month of treatment. These areas became violaceous,.