Publication:

Off-label uses of botulinum toxin A in chronic itch-related dermatological disorders: a retrospective study

Background Botulinum neurotoxin (BONT) produced by anaerobic clostridium botulinum exerts diverse biological effects by acting on various neurotransmitters like acetylcholine, substance P, glutamate, mast cell, calcitonin gene related peptide (CGRP). Initially linked with aesthetic dermatology, it is now explored in various dermatological conditions including rosacea, post-herpetic neuralgia, keloid and hypertrophic scars and itch related disorders.  The aim to investigate the diverse dermatological applications of BONT A in chronic itch disorders and evaluate its therapeutic outcomes in a retrospective study.

Methods A retrospective, single centre study was conducted from December 2018 to December 2023. Information of all patients who underwent intradermal botulinum toxin injections for chronic itch-related disorders was extracted from the database. Information including demographic profiles, diagnosis, previous medications, the dosage of toxin administered, duration of symptomatic relief and post-procedure complications were recorded. Treatment efficacy was assessed based on the patient reported improvement: mild (1-24%), moderate (25-49%, good (50-75%) and excellent (>76% improvement).

Result A total of 33 patients (22 female and 11 male) were enrolled with diagnoses such as pruritus vulvae, scrotal dysesthesia, post-herpetic neuralgia, notalgia paresthetica, lichen simplex chronicus, and burning foot syndrome. Toxin was injected as 1 unit/cm2 and total number of toxins administered depended on the area involved. Majority of patients reported good improvement (50-75%) in itching lasting for 3-5 months.

Conclusion Intradermal BONT A injection showed promising long-lasting results in managing chronic itch related disorders which do not respond to conventional modalities of treatment.