Prolonged Antipruritic Effect of Botulinum Toxin Type A on Cowhage-induced Itch: A Randomized, Single-blind, Placebo-controlled Trial.

Botulinum toxin type A (Botox) is thought to have antipruritic effects through inhibition of pruritic factors, including acetylcholine, substance P, and glutamate. The aim of this randomized, single-blind, placebo-controlled trial was to test the effect of botulinum toxin type A on cowhage, a non-histaminergic model for chronic itch. Botulinum toxin type A was injected into the arm of 35 healthy subjects, with a saline control injected into the contralateral arm. Thermal sensory parameters (warmth and heat thresholds and heat pain intensity) and itch intensity after cowhage application were examined on test areas. Botulinum toxin type A reduced itch intensity, overall perceived itch (area under the curve (AUC); percentage change from baseline), and peak itch intensity compared with the control at 1 week, 1 month, and 3 months. Botulinum toxin type A had no effect on thermal thresholds or heat pain intensity. In conclusion, botulinum toxin type A reduced cowhage itch for at least 3 months, which suggests that botulinum toxin type A is a potential long-lasting treatment for localized, non-histaminergic itch.

Guillain-Barre syndrome associated with peginterferon alfa-2a for chronic hepatitis C: A case report.

The recommended therapy for chronic hepatitis C (CHC) infection is the combination of a Pegylated interferon and Ribavirin. Almost all such patients on combination therapy experience one or more adverse events during the course of treatment. Significant neurological side effects are rare. A few cases of Bell's Palsy, chronic inflammatory demyelinating polyneuropathy and even one case of acute demyelinating polyneuropathy with atypical features for Guillain-Barre syndrome (GBS) associated with Interferon therapy have been reported but no report of GBS with typical features has been published. We present a case report of typical GBS associated with Peginterferon alfa-2a and Ribavirin used for treatment of CHC infection.