Botulinum toxin is used with remarkable success to treat various muscle and exocrine gland hyperactivity syndromes. Rarely, treatment failure due to formation of botulinum toxin antibodies (ABF) occurs. To reduce the risk of ABF, a new formulation of Botox (in the following "current Botox"; Allergan, Irvine, California, USA) with increased specific biological potency was introduced. Here we report the case of a 50-year-old woman who developed ABF despite receiving current Botox.
