Intralesional Botulinum Toxin A Injection for Recalcitrant Alopecial Totalis and Alopecia Universalis: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

Background: Alopecia totalis (AT) and alopecia universalis (AU) have a high rate of recurrence and are very difficult to treat. To date, no consensus has been reach among clinicians regarding the best way to treat these conditions. It was recently proposed that botulinum toxin type A (BT) injection in alopecia areata may inhibit unmyelinated C fibers from releasing substance P and calcitonin-gene-related protein (CGRP), which showed a favorable clinical response in cephalalgic alopecia areata.
Objective: To investigate the efficacy of botulinum toxin type A (BT) in the treatment of recalcitrant AT and AU.
Methods: Twenty patients with either recalcitrant AT or AU were enrolled in this study. One half of the scalp was injected with BT 50 units 2.5 ml intradermally (dilution 20 units/ml) and the other half of the scalp was injected with normal saline 2.5 ml. Clinical assessments were performed using Severity of Alopecia Tool (SALT) score, scalp mapping, and photography. Patients were followed up monthly for 4 months after treatment to evaluate terminal hair regrowth.
Results: Based on patient results at the 4-month follow-up, no clinical improvement in either recalcitrant alopecia totalis or alopecia universalis was observed.
Conclusion: Although BT has been demonstrated to improve the clinical features of cephalalgia alopecia areata, BT was not shown to improve the clinical features of recalcitrant AT or AU in this study. In order to understand and explain the differences in these two clinical outcomes using BT in alopecia, further investigation is needed.