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

This study investigated the efficacy of botulinum toxin type A (BT) in treating recalcitrant alopecia totalis (AT) and alopecia universalis (AU) in 20 patients. Each patient's scalp was divided, with one half receiving BT injections and the other half receiving saline. After 4 months of follow-up, no clinical improvement in hair regrowth was observed in either AT or AU cases. The study concluded that while BT has shown benefits in cephalalgia alopecia areata, it did not improve recalcitrant AT or AU, indicating a need for further research to understand these differing outcomes.