Botulinum toxin type A improves pain in numb chin syndrome.

Numb chin syndrome is a rare pain disorder characterized by decreased sensation and paresthesia in the territory of the mental nerve. Neuropathic pain is sometimes described in this setting, and the most common treatments include oral analgesics, gabapentinoids, and carbamazepine; however, botulinum toxin type A has never been used in this setting. We describe a case of bilateral numb chin syndrome, secondary to Burkitt lymphoma, associated with refractory and persistent burning neuropathic pain, effectively treated twelve times with subcutaneous Botulinum toxin type A (BoNT/A) injections. The procedure was well tolerated, but the patient reported incomplete mouth closure of minimal entity. BoNT/A could be a safe and effective therapy for neuropathic pain associated with numb chin syndrome.