INTRADERMAL botulinum toxin A for post acne erythema outperformed broadband light in this split face randomized controlled trial.
Study Design of Intradermal Botulinum Toxin A For Post Acne Erythema
Post acne erythema is a frequent aesthetic concern in patients whose inflammatory acne has settled but who remain troubled by persistent facial redness. In this single center split face study from China, 30 adults with post acne erythema were enrolled and each cheek was assigned to a different treatment. One randomly selected cheek received a single session of intradermal botulinum toxin A injection, while the contralateral cheek underwent three broadband light treatments at one month intervals.
Investigators assessed multiple objective and clinical measures at baseline and during three months of follow up. Outcomes included the Clinician Erythema Assessment score, erythema index from imaging systems, colorimetric a* values, sebum secretion, transepidermal water loss, skin hydration and adverse events. Pain intensity was recorded using a visual analog scale, and patient satisfaction was also captured for both treatment sides.
Efficacy Versus Broadband Light Over Three Months
Baseline characteristics were similar between the intradermal botulinum toxin A and broadband light sides. At one month, the botulinum toxin A treated cheeks showed significantly greater reductions in Clinician Erythema Assessment, erythema index, a* value and sebum secretion compared with the broadband light treated cheeks. The superiority in sebum reduction on the botulinum toxin A side persisted at both two and three months. In addition, reduction in Clinician Erythema Assessment remained significantly greater at two months and improvement in a* value was significantly greater at three months for the injection side.
Both intradermal botulinum toxin A and broadband light produced overall trends toward lower erythema index, transepidermal water loss, Clinician Erythema Assessment scores, sebum secretion and a* values relative to baseline, alongside increased skin hydration. These findings suggest that each modality can contribute to improvement in post acne erythema, although intradermal botulinum toxin A produced faster and more pronounced changes in several parameters.
Safety, Patient Experience, And Clinical Implications
Pain scores were higher with intradermal botulinum toxin A than with broadband light, reflecting the discomfort of multiple intradermal injections. Despite this, patient satisfaction did not differ significantly between the two treatments and the safety profile appeared comparable, with no concerning adverse events reported in either group over three months.
For clinicians managing patients distressed by persistent facial erythema and textural acne scars, these data position intradermal botulinum toxin A as a promising option that may provide meaningful redness and sebum reduction with a single session. At the same time, the small sample size, single center design and short follow up highlight the need for larger and longer studies before intradermal botulinum toxin A for post acne erythema can be widely incorporated into routine acne management.
Reference: Yang L et al. Efficacy and safety of intradermal botulinum toxin A for post-acne erythema: a split-face randomized controlled trial. Front Med. 2025;12:1610125.
