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 burning, tingling, itching, or numbness, most commonly in the face. This occurs 1-2 hours after the beginning of exposure and resolves spontaneously.


RESULTS
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 alpha-cyano group generally showing the weakest effect.


CONCLUSIONS
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.
Wilks
M F
MF
Medical Toxicology Unit, Guy's & St. Thomas' Hospital Trust, London, United Kingdom. Martin.Wilks@gstt.sthames.nhs.uk
D000287:Administration, Topical; D000818:Animals; D004195:Disease Models, Animal; D006168:Guinea Pigs; D006801:Humans; D007306:Insecticides / Q000009:adverse effects*; D016273:Occupational Exposure / Q000009:adverse effects; D010292:Paresthesia / Q000139:chemically induced* / Q000503:physiopathology; D011722:Pyrethrins / Q000009:adverse effects*; D012867:Skin / Q000187:drug effects*
D007306:Insecticides; D011722:Pyrethrins