Low-Dose OnabotulinumtoxinA using Seven-Point Pattern Intradermal Injections in Patients with Moderate-to-intolerable Primary Axillary Hyperhidrosis: A Single-Blinded, Side-by-Side Randomized Trial.

[BACKGROUND] The axilla is the most common site for primary hyperhidrosis (HH) affecting quality of life. No consensus on the optimal doses of botulinum toxin (BTX) has been established.

[OBJECTIVE] This study aimed to scrutinize the effectiveness of 25- and 50-U onabotulinumtoxinA in patients with moderate-to-intolerable primary axillary HH as well as pain scores after BTX injection.

[METHODS] A single-blinded, side-by-side randomized trial was conducted between January and June 2022. Participants were randomly treated with 25-unit (U) onabotulinumtoxinA in one axilla and 50-U onabotulinumtoxinA in the other. The Minor starch-iodine test and gravimetric testing, the Hyperhidrosis Disease Severity Scale (HDSS), Hyperhidrosis Quality of Life Index (HidroQoL), global self-assessment scale (GSAS), and satisfaction scores were collected and analyzed.

[RESULTS] A total of 12 participants were included in the final analysis; six (50.0%) were female. The median age was 30.3 (interquartile range: 28.7-32.3) years. No statistically significant differences were noted in the sweat rate production, hyperhidrotic area, HDSS, HidroQoL, GSAS, and satisfaction scores between 25- and 50-U BTX at any follow-up visit. No significant difference was noted in pain scores between the two groups (=0.810).

[CONCLUSION] Low-dose onabotulinumtoxinA is associated with similar efficacy and safety outcomes in primary axillary HH treatment as is conventional-dose onabotulinumtoxinA. No difference was noted in injection site pain between the two groups.