Post-Botulinum Headache in Cosmetic Practice: A Prospective Study.

[BACKGROUND] Botulinum toxin is widely used for aesthetic and functional indications and is generally considered safe; however, post-procedural headache remains a recognized but underexplored adverse effect, particularly in cosmetic practice.

[OBJECTIVE] To evaluate the incidence, characteristics, and potential risk factors of headache following botulinum toxin injections administered to different anatomical regions.

[METHODS] This prospective observational study included 102 adult patients undergoing abobotulinumtoxinA injections to the upper facial regions, masseter muscles, and/or axillary area. Headache occurrence was assessed on day 3 by telephone, at days 10-12 during follow-up visits, and through patient-initiated contact within the first month. Demographic variables, prior botulinum toxin exposure, injection-related pain, toxin dose, and headache characteristics were recorded.

[RESULTS] Post-botulinum headache occurred in 13 patients (12.7%) and was generally mild-to-moderate, short-lived, and self-limited. Headache was significantly more frequent in first-time recipients compared with previously treated patients (45.5% vs. 8.8%, p = 0.005). All patients who developed headache had received injections involving the upper facial regions, whereas no headache was observed after exclusive masseter or axillary treatments. No associations were found with toxin dose, procedural pain, or systemic comorbidities.

[CONCLUSION] Post-botulinum headache is an infrequent, benign, and transient event, predominantly affecting first-time patients undergoing upper facial injections. These findings may aid clinicians in patient counseling and expectation management.