Causes of Botulinum Toxin Treatment Failure

PURPOSE: The purpose of this article is to review the cause of botulinum toxin (BT) failure and determine the ways to minimize the risks of its occurrence. METHODS: A PubMed and Google Scholar literature search was conducted with the search terms botulinum toxin, treatment, failure, causes, and prevention. Fifteen relevant articles were found and used as the scientific base for this article. RESULTS: The failure of BT therapy is associated with immunogenic and non-immunogenic causes and the formation of neutralizing antibodies toward the active components of BT or the complexing proteins. Enzyme-linked immunosorbent assay (ELISA) testing and mouse hemidiaphragm assay (MHA) can diagnose the failure. The risk of developing treatment failure can be minimized by using complexing protein-free formulations, selecting a treatment regimen with the least immunogenicity, proper injection technique, and gentle product handling. CONCLUSION: The treatment failure can compromise the success of BT treatment. Current medical literature shows controversial evidence for and against BT immunogenicity. Therefore, the cause of BT failure is likely to be multifactorial.