Battling Neuropathic Scar Pain With Botulinum Toxin

Botulinum toxin type A (BTA) is a neurotoxic protein that prevents the release of neurotransmitters from presynaptic nerves and has shown promise in treating neuropathic pain. Recently, BTA has been used to treat painful keloids and scars. We present a patient with refractory neuropathic pain in a normotrophic spread-scar treated with the injection of BTA. A 47-year-old Caucasian female with a history of invasive melanoma of the left upper arm presented with pain in her excision scar, which she described as a “pins and needles” sensation alternating with a dull, deep ache. She had previously tried topical lidocaine, topical and intralesional steroids, and oral gabapentin without improvement. We treated the patient with 50 U of onabotulinumtoxinA intradermally at 1-1.5 cm intervals within and immediately around the perimeter of the scar. At 1-week follow-up, she reported a 10% decrease in her pain. Four weeks after the procedure, she reported a 50% decrease in pain with smoothening of the scar surface, which has been durable for over 5 months. Scar pain can significantly impair quality of life and treatment protocols have not been established for normotrophic scars. Many trials have focused on improving appearance and reducing symptoms in hypertrophic and keloid scars, but few have evaluated therapies for normotrophic scars. BTA has been studied as a treatment for painful hypertrophic and keloid scars with promising results. Our patient had a marked reduction in pain and improvement in scar texture at 1-month follow-up, which has been maintained thus far, indicating that intradermal BTA may be a simple and useful tool in treating painful normotrophic scars. J Drugs Dermatol. 2019;18(9):937-938.