Botulinum Toxin Type A to Improve Facial Symmetry in Facial Palsy: A Practical Guideline and Clinical Experience

Toxins (Basel). 2021 Feb 18;13(2):159. doi: 10.3390/toxins13020159.


Unilateral peripheral facial nerve palsy jeopardizes quality of life, rendering psychological consequences such as low self-esteem, social isolation, anxiety, and depression. Among therapeutical approaches, use of Botulinum toxin type A (BoNT-A) on the nonparalyzed side has shown promising results and improvement of quality of life. Nevertheless, the correct technique is paramount, since over-injection of the muscles can result in lack of function, leading to a "paralyzed" appearance, and even worse, functional incompetence, which may cause greater distress to patients. Therefore, the objective of this article is to provide a practical guideline for botulinum toxin use in facial palsy. To this aim, adequate patient assessment, BoNT-A choice, injection plan and dosage, and injection techniques are covered.

Keywords: botulinum toxin A; facial asymmetry; facial palsy; facial paralysis; incobotulinum-toxin A; neurotoxin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Acetylcholine Release Inhibitors / administration & dosage*
  • Acetylcholine Release Inhibitors / adverse effects
  • Adult
  • Bell Palsy / diagnosis
  • Bell Palsy / drug therapy*
  • Bell Palsy / physiopathology
  • Botulinum Toxins, Type A / administration & dosage*
  • Botulinum Toxins, Type A / adverse effects
  • Facial Muscles / drug effects*
  • Facial Muscles / physiopathology
  • Facial Paralysis / diagnosis
  • Facial Paralysis / drug therapy*
  • Facial Paralysis / physiopathology
  • Female
  • Humans
  • Injections, Intramuscular
  • Quality of Life
  • Treatment Outcome


  • Acetylcholine Release Inhibitors
  • Botulinum Toxins, Type A