Pyrethroid-Induced Paresthesia—A Central or Local Toxic Effect?

Abstract

Background: Pyrethroid-induced paresthesia is frequently seen after dermal exposure to pyrethroids. Affected individuals experience a sensation of burning, tingling, itching, or numbness, most commonly in the face. This occurs 1–2 hours after the beginning of exposure and resolves spontaneously. Mechanisms: Paresthesia occurs as a result of a direct effect on intracutaneous nerve endings at very low pyrethroid doses. It is related to potency of the pyrethroid with pyrethroids without an α-cyano group generally showing the weakest effect. Conclusion: Doses sufficient to cause paresthesia are far lower than those causing central or systemic toxicity. Paresthesia is therefore considered to be a localized nuisance effect. The best advice to affected individuals is to prevent paresthesia from occurring through appropriate hygiene measures and personal protection.