Beyond the axilla: The evolving role of botulinum toxin in the treatment of facial, scalp, and focal hyperhidrosis.

Botulinum toxin type A is an established treatment for focal hyperhidrosis of the axillae and palms, but its use has recently expanded to include craniofacial, facial, and scalp hyperhidrosis. This systematic review with narrative synthesis evaluates the clinical use of botulinum toxin type A for focal hyperhidrosis across multiple anatomic sites. A structured search of PubMed/MEDLINE, Embase, and Scopus was conducted for English-language human studies published between 2000 and 2025. Original clinical studies reporting outcomes related to sweat reduction, disease severity, quality of life, duration of effect, or adverse events were included, whereas reviews and non-original publications were used only for background and citation tracking. A total of 13 original clinical studies met the inclusion criteria. Evidence was strongest for axillary hyperhidrosis, with randomized controlled trials consistently demonstrating substantial reductions in sweating and sustained patient-reported benefits. Palmar hyperhidrosis showed reliable efficacy, although treatment was limited by injection discomfort and transient weakness. Evidence for craniofacial, facial, and scalp hyperhidrosis consisted primarily of small cohorts and case series that nevertheless reported meaningful symptom improvement and acceptable safety profiles, despite heterogeneity in dosing and injection techniques. Overall, botulinum toxin type A remains a cornerstone therapy for focal hyperhidrosis, and although evidence beyond the axillae is less robust, available data support its use in selected patients and underscore the need for larger, standardized studies of craniofacial and scalp hyperhidrosis.