How effective is botulinum toxin A (BTA) in treating keloids and hypertrophic scars?

Updated: May 29, 2020
  • Author: Brian Berman, MD, PhD; Chief Editor: Dirk M Elston, MD  more...
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In an in vitro study, 64% of cultured fibroblasts were found to be in the G0-G1 phase of the cell cycle when exposed to BTA, while 35.4% were in the proliferative phases (ie, G2, M, S). In comparison, cultured fibroblasts that were not exposed to BTA had the following distribution: 36% (G0-G1) and 64% (proliferative phases). [58] The effect of BTA on the cell cycle distribution of fibroblasts may indicate that BTA can improve the eventual appearance of and inhibit the growth of hypertrophic scars and keloids.

In a prospective, uncontrolled study evaluating the effects of BTA in the treatment of keloids, 12 keloids were injected intralesionally at a concentration of 35 U/mL, with the total dose varying from 70-140 U per session. Injections were given at 3-month intervals for a maximum of 9 months. At 1-year of follow up, the therapeutic outcomes were excellent (n = 3), good (n = 5), and fair (n = 4), with no patients failing therapy or showing signs of recurrence. [59]

Nineteen patients with hypertrophic scars received intralesional injections of BTA (2.5 U/mL at 1-mo intervals) for 3 months. All patients showed acceptable improvement of the scars at 6 months of follow up. The erythema, pruritus, and pliability scores were significantly lower post-BTA injections compared with baseline. [60]

In a case series, 12 patients (n=10 whites, n=01 Chinese, and n=01 South Asian) with keloids in different parts of the body (n=9 presternal; n=3 neck, thigh, and cheek), previously treated with conventional modalities, received between 20 and 100 units of BTA on each visit over the past 5 years (no frequency specified). Eight patients had concurrent alternating intradermal triamcinolone injections. Complete flattening of the keloids was obtained after a range of 2-43 months of repeated injections. Two of 12 patients had recurrences adjacent to previously treated areas. One patient developed atrophy, leading to ulceration and further recurrence. [61]

Intramuscular injections of BTA along with scar revision techniques on the face may help to reduce the development of a wider scar. [62]

Larger, randomized, controlled studies are warranted to determine the role of BTA in the treatment of keloids and hypertrophic scars.

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