Antibody‐Induced Failure of Botulinum Toxin Type A Therapy in a Patient with Masseteric Hypertrophy

BACKGROUND: With the expanding use of botulinum toxin, much concern about the antibody against botulinum toxin is arising. Unlike neurologic indications such as cervical dystonia, antibody-induced failure of botulinum toxin therapy has never been reported in the cosmetic field. OBJECTIVE: The objective was to describe a case of an antibody-induced failure of botulinum toxin type A (BTX-A) therapy (BOTOX, Allergan, Inc.) that occurred in a patient with masseteric hypertrophy. METHODS AND MATERIALS: We present a 20-year-old girl who developed antibody-induced therapy failure after the fourth injection series. Sixty units of toxin was injected at each series and the intertreatment interval was four to five months. RESULTS: Frontalis test revealed no paresis of muscle after a unilateral injection of BTX-A. Circulating antibodies against BTX-A were detected by indirect enzyme-linked immunosorbent assay and mouse protection assay. CONCLUSION: This case is unique in that, first, immunoresistance developed in a patient of cosmetic indication where only a small dose of BTX-A was administered and, second, antibodies developed on the so-called new formulation of BOTOX. Our case alerts cosmetic surgeons to the importance of antibody against the botulinum toxin.