Randomized Split-Side Study Comparing Efficacy of Botulinum Toxin Type A Versus 0.9% Sodium Chloride in Scalp Psoriasis

This randomized, split-side, double-blinded, placebo-controlled study evaluated the efficacy of botulinum toxin type A (62.5 units) versus 0.9% sodium chloride in treating scalp psoriasis in 14 patients. The primary endpoint was a 50% reduction in the modified Psoriasis Severity Index (mPSI50) at weeks 2, 4, 8, and 12. Results showed that botulinum toxin type A significantly reduced psoriasis severity compared to placebo, with mPSI50 achieved in 21%, 50%, 57%, and 43% of patients at the respective time points, versus 0%, 7%, 29%, and 14% for placebo. No serious side effects were reported, suggesting botulinum toxin type A as a potential adjuvant therapy for recalcitrant scalp psoriasis.