INTRADERMAL BOTULINUM TOXIN FOR ERYTHEMATOTELANGIECTATIC ROSACEA: MECHANISMS, DOSING AND SAFETY

Erythematotelangiectatic rosacea is a chronic inflammatory and neurovascular facial dermatosis characterized by persistent centrofacial erythema, flushing, telangiectasia, burning, stinging, and marked impairment of quality of life. Although topical alpha-adrenergic agonists, vascular lasers, intense pulsed light, systemic anti-inflammatory agents, and skin barrier-directed interventions are widely used, persistent erythema and flushing often remain difficult to control. Intradermal botulinum toxin type A has emerged as a promising off-label therapeutic option for refractory vascular rosacea. Its effect is no longer interpreted solely through neuromuscular blockade. Current evidence suggests that botulinum toxin type A may reduce erythema and flushing through modulation of acetylcholine-dependent vasodilation, inhibition of vasoactive neuropeptides such as substance P and calcitonin gene-related peptide, suppression of mast cell degranulation, interference with LL-37/MRGPRX2-mediated inflammation, downregulation of vascular endothelial growth factor-driven angiogenesis, and improvement of skin quality parameters including sebum production and pore appearance. Clinical studies, including case series, prospective cohorts, split-face trials, and meta-analyses, indicate reductions in erythema, flushing severity, vascular density, and patient-reported symptoms after intradermal or microdroplet injections. However, the literature remains limited by small sample sizes, heterogeneous dosing regimens, short follow-up, variable toxin formulations, and inconsistent outcome measures. This review summarizes the mechanistic rationale, clinical efficacy, injection protocols, safety profile, limitations, and future directions of intradermal botulinum toxin type A in erythematotelangiectatic rosacea.