Efficacy of Intralesional Botulinum Toxin A for Treatment of Painful Cutaneous Leiomyomas: A Randomized Clinical Trial.

[IMPORTANCE] Cutaneous leiomyomas can be associated with severe paroxysmal pain in which nerve conduction may have a key role. Medical management of painful cutaneous leiomyomas is generally unsatisfactory.

[OBJECTIVE] To assess the efficacy of intralesional botulinum toxin A in the management of pain associated with cutaneous leiomyomas.

[DESIGN, SETTING, AND PARTICIPANTS] Randomized, double-blind, placebo-controlled pilot study conducted from January 5, 2009, to March 27, 2014. The setting was a single-center study at the National Institutes of Health among participants 18 years or older with cutaneous leiomyomas characterized by pain at least once weekly and pain of at least 4 on a pain scale ranging from 0 to 10.

[INTERVENTIONS] Eighteen participants were randomized to receive intralesional botulinum toxin A (5 U per 1 cm2) or equivalent volumes of intralesional saline placebo.

[MAIN OUTCOMES AND MEASURES] The primary outcomes were the differences in average lesional pain assessed by the Brief Pain Inventory and visual analog scale before and after ice provocation over a 4-week period.

[RESULTS] No significant difference in average lesional pain was observed between the study arms. Decreased pain was reported in the botulinum toxin vs placebo arms by visual analog scale scores before ice provocation (median, 0.00; range, -3.30 to 0.70 for botulinum toxin and median, 0.40; range, -1.30 to 1.50 for placebo; P = .06); however, this finding was nonsignificant. No significant difference was observed in change in pain after ice provocation. A significant difference was seen between the arms in skin-related quality of life by total Dermatology Life Quality Index (median, -4.00; range, -8.00 to 2.00 for botulinum toxin and median, 0.00; range, -1.00 to 4.00 for placebo; P = .007) and with the specific skin pain-related question on the Dermatology Life Quality Index (median, -1.00; range, -2.00 to 1.00 for botulinum toxin and median, 0.00; range, -1.00 to 0.00 for placebo; P = .048). No significant difference was found in pain as ascertained by Patient Global Impression of Change at week 4. No serious adverse events related to botulinum toxin use were observed.

[CONCLUSIONS AND RELEVANCE] The use of botulinum toxin to treat painful cutaneous leiomyomas was associated with improved quality of life and with a trend toward improved pain at rest.

[TRIAL REGISTRATION] clinicaltrials.gov Identifier: NCT00971620.