Beyond Muscle: A Narrative Review of Onabotulinum Toxin A for Skin Quality

September 2021 | Volume 20 | Issue 9 | Original Article | 958 | Copyright © September 2021


Published online August 19, 2021

Marc M. Beuttler MDa, Haley D. Harrington MDb, Deirdre O. Hooper MDa,c

aLouisiana State University Health Sciences Center, New Orleans, LA
bOrlando Regional Medical Center, Orlando, FL
cAudubon Dermatology, New Orleans, LA

Abstract
Background: Onabotulinum toxin A’s (BoNTA’s) popularity is centered on its quick, predictable, and safe ability to improve clinically apparent rhytides. While this remains the only FDA indication for BoNTA, recent research suggests that BoNTA may have a much wider use for the improvement of overall skin quality.
Objective: This review will focus on the various evidence and uses of BoNTA for improvement of skin quality.
Materials and Methods: This review considered published journal articles (clinical trials, case studies, scientific reviews). Studies were identified by searching the PubMed database and reference lists of respective articles. Only articles available in English were considered for this review.
Results: Intramuscular and intradermal injections of BoNTA decrease sebum production, pore size, facial erythema and flushing, and resting lines. BoNTA induces neocollagenesis and restores the extracellular matrix.
Conclusion: The literature provides both in vivo and in vitro evidence that BoNTA enhances skin quality beyond its well-studied neuromuscular effect.

J Drugs Dermatol. 2021;20(9):958-962. doi:10.36849/JDD.6038

INTRODUCTION

Onabotulinumtoxin A’s (BoNTA’s) clinical utility was first proven in the late 1960s, when it was used for the correction of nonaccommodative strabismus. Since then, the use of BoNTA as a neuromodulator has expanded substantially. The first formal report of BoNTA’s aesthetic use was in 1989, and in 2002 the FDA approved the use of BoNTA for glabellar lines.1 Its popularity has continued to grow. Injection of BoNTA was the most performed non-surgical procedure by plastic surgeons in 2019, and between 2015 and 2019, there has been a 17.8% increase in the overall number of BoNTA procedures.2 The popularity of BONTA has largely been based on its anticholinergic activity at the neuromuscular junction. BONTA prevents the release of acetylcholine from the presynaptic terminal, which effectively prevents the contraction of muscle fibers, thereby blocking the formation of rhytides. While this understanding forms the basis of its current aesthetic use, BoNTA’s effects may cumulatively serve to improve the overall quality of the skin.3 Studies examining the use of Botulinum toxins (BoNTs) to improve pore size, sebum production, skin quality, facial flushing, collagen deposition, scar healing, and wound remodeling point the way to a wider application of BoNTs. Indeed, new dermatologic research employs BoNTA for a much broader range of cellular targets, including dermal fibroblasts, sebocytes, and vascular endothelial cells.5 This article will review uses of BoNTA that specifically show promise for improving skin quality by reducing sebum production, pore size, and facial erythema, or by stimulating collagen deposition and remodeling.

Sebum Production and Pore Size
Oily skin, an extremely common patient complaint, is caused by several variable factors. Sebum production varies from person to person and changes throughout the course of one’s life. The duct of the sebaceous gland connects to the infundibulum of the hair follicle, corresponding to a skin pore. Overproduction of sebum by sebocytes leads to the development of oily skin, and is associated with enlarged pores, acne, and seborrheic dermatitis, all of which have negative effects on patient well-being and cosmetic outcome. Despite the number of treatments available for decreasing sebum production and pore size, therapeutic efficacy is variable and can be associated with unwanted side effects.5 As the popularity and indications for BoNTA evolve, many reports suggest that intramuscular and intradermal injections of BoNTA are both efficacious in decreasing sebum production and pore size.

Shuo et al performed a retrospective review of 13 published studies examining BoNTA’s possible treatment mechanisms for