Efficacy and safety of botulinum toxin A in the treatment of female pattern hair loss.

[BACKGROUND] Female pattern hair loss (FPHL) is the most prevalent type of alopecia among adult women. Presently, topical minoxidil stands as the sole treatment endorsed by the FDA. Addressing cases of FPHL in individuals who develop contact dermatitis in response to minoxidil can pose a challenge for dermatologists.

[OBJECTIVE] To assess the efficacy and safety of subcutaneous injections of Botulinum Toxin Type A (BTA) in treating FPHL.

[METHODS] Enrolled outpatients with FPHL who exhibited an allergic reaction to minoxidil solution. Diagnosis of FPHL was established through clinical examination and trichoscopy. Inclusion criteria involved patients with no prior treatment within the last year and without any comorbidities. BTA, specifically 100 units, was mixed with 2 mL of 0.9% normal saline. Twenty injection target sites, spaced 2-3 cm apart, were symmetrically marked on the hairless area of the scalp. A dosage of five units was intradermally injected at each target site. Representative photographs and dermoscopic images of the scalp were captured before and after 3 months of treatment.

[RESULTS] A total of 10 FPHL, aged between 26 and 40 years, were included. The average age was 30.3 ± 4.64 years, and all patients had a positive family history of Androgenetic Alopecia. The average duration of the disease was 3.70 ± 1.42 years. According to patients' self-assessment, after 1 month of treatment, 10 FPHL patients reported experiencing moderate to marked improvement in symptoms related to scalp oil secretion. Three months later, dermatological assessments showed that three had mild improvement, six had no change, and one had a worsening condition. No adverse effects were observed.

[CONCLUSIONS] Our study suggests that the effectiveness of BTA for FPHL is limited to 3 months. However, it can be considered for tentative use after effective communication with patients. The long-term efficacy and safety of BTA in treating FPHL require further observation and study.