Topical cetirizine shows higher clinical improvement for female androgenetic alopecia

Androgenetic alopecia (AGA) is the most frequent cause of hair loss in both genders, with a higher psychological impact on females. Minoxidil currently is the only FDA-approved treatment for female androgenetic alopecia (FAGA), and it needs lifelong application and causes side effects. Prostaglandins (PGs) may play a role in hair growth, PGF and PGE increase hair growth, but prostaglandin D2 (PGD2) inhibits it, increases sebaceous hyperplasia, and is elevated in bald scalp. Cetirizine is an antihistamine that increases PGE, inhibits PGD2 and reduces inflammatory cell infiltrate, making it a potentially safe treatment for androgenetic alopecia.

In the randomized, double-blind, controlled, parallel study conducted at Dermatology Clinic, Cairo University Teaching Hospital, Egypt, Eglal A. Bassiouny and colleagues aimed to compare the safety and efficacy of topical cetirizine with minoxidil (group 1) versus s topical minoxidil with placebo (group 2) in female patients with androgenetic alopecia. "To the best of our knowledge, this is the first study on cetirizine as an add-on in female androgenetic alopecia," they wrote.

The study included sixty-six patients with female AGA aged 20-50 years, Sinclair (II–IV). The trichoscopic parameters, side effects, patients' self-assessment, and global photographic assessment were evaluated. They were randomly assigned to either group 1 or 2 for 24 weeks.

The authors reported the following findings:

· There was a statistically significant change from baseline in frontal and vertex terminal and vellus hair density with a significant increase in vertex hair shaft thickness and an average number of hairs per follicular unit in group 1.

· Patients reported significantly better scores in patient self-assessment in group 1.

· Side effects were not significantly different between groups.

To conclude, cetirizine may lead to clinical improvement in FAGA and increases shaft thickness with no side effects making it a potential therapy for FAGA.

"Pharmacokinetic studies on dose-dependent hair growth and its bioavailability in follicular hair sheath are recommended along with studies to evaluate the drug's exact mechanism of action, the efficacy of its oral dosage form and other H1-blockers, and its effectiveness in other alopecia types," the researchers wrote. More studies are required to determine whether topical cetirizine alone or oral cetirizine is effective.

Reference:

Bassiouny, E.A., El-Samanoudy, S.I., Abbassi, M.M. et al. Comparison between topical cetirizine with minoxidil versus topical placebo with minoxidil in female androgenetic alopecia: a randomized, double-blind, placebo-controlled study. Arch Dermatol Res (2022). https://doi.org/10.1007/s00403-022-02512-2