Pyrethroid-induced paresthesia - A central or local toxic effect?

Background: Pyrethroid-induced paresthesia is frequently seen after dermal exposure to pyrethroids. Affected individuals experience a sensation of bur ning, tingling, itching, or numbness, most commonly in the face. This occur s 1-2 hours after the beginning of exposure and resolves spontaneously. Mec hanisms: Paresthesia occurs as a result of a direct effect on intracutaneou s nerve endings at very low pyrethroid doses. It is related to potency of t he pyrethroid with pyrethroids without an a-cyano group generally showing t he weakest effect. Conclusion: Doses sufficient to cause paresthesia are fa r lower than those causing central or systemic toxicity, Paresthesia is the refore considered to be a localized nuisance effect. The best advice to aff ected individuals is to prevent paresthesia from occurring through appropri ate hygiene measures and personal protection.