The Randomized Double-Blind Placebo-Controlled Trial of Intralesional Botulinum Toxin A Injection for Recalcitrant Alopecia Totalis and Alopecia Universalis

The study investigated the use of intralesional botulinum toxin A injections as a treatment for recalcitrant alopecia totalis and alopecia universalis. These conditions were known to be difficult to treat with a high rate of recurrence. The hypothesis was that botulinum toxin A could inhibit unmyelinated C fibers from releasing substance P and CGRP, potentially preventing the destruction of hair follicles. The study aimed to evaluate the clinical response of this treatment approach, although the document does not provide specific results or the number of participants involved in the trial.