Botulinum Toxin in the Treatment of Hair and Scalp Disorders: Current Evidence and Clinical Applications.

Botulinum toxin (BoNT) is well-recognized throughout dermatology for its cosmetic indications and growing therapeutic value. Recent studies have trialed BoNT in the treatment of hair and scalp disorders, many of which lack long-term effective treatments and significantly impact quality of life. In this review, we summarize the current clinical literature on this topic to comprehensively evaluate the efficacy, safety, and clinical value of BoNT in treating hair and scalp conditions. A literature search on PubMed/MEDLINE and Scopus identified 40 articles reporting the use of 25-200 units of BoNT-A or B in 689 patients with hair loss (79.5%), scalp seborrheic dermatitis/hyperseborrhea (10%), craniofacial hyperhidrosis (9%), folliculitis decalvans/dissecting folliculitis (0.86%), scalp pain (0.43%), or linear scleroderma (0.29%). Most studies on BoNT therapy for androgenetic alopecia (AGA) reported mild or non-significant hair growth; however, considerable variability in outcome measures complicates the ability to draw definitive conclusions or justify the use of BoNT over established AGA therapies. BoNT-A and B showed consistent efficacy in treating craniofacial hyperhidrosis with minimal side effects. Additional scalp conditions may benefit from BoNT therapy, but the evidence is limited, and larger, controlled studies are needed to better understand BoNT's clinical value in these conditions.