Botulinum neurotoxin injections are a valuable treatment modality for many therapeutic indications as well as in the aesthetic field for facial rejuvenation. As successful treatment requires repeated injections over a long period of time, secondary resistance to botulinum toxin preparations after repeated injections is an ongoing concern. We report five case studies in which neutralizing antibodies to botulinum toxin type A developed after injection for aesthetic use and resulted in secondary treatment failure. These results add to the growing number of reports in the literature for secondary treatment failure associated with high titers of neutralizing antibodies in the aesthetic field. Clinicians should be aware of this risk and implement injection protocols that minimize resistance development.

Most of the parameters measured on the lips have similar variations than the same parameters measured on the skin. Only sebum and color appear being dependant on the hormonal status.

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 . Trial registration NCT02353897.

No abstract

No abstract