title: Threshold responses in formaldehyde-sensitive subjects.
abstract: Patch tests with three low concentrations of formaldehyde were applied continuously in formaldehyde-sensitive subjects for 1 wk. The closed patch test method produced a response to 30 parts per million (ppm) in some subjects by 120 continuous hours of testing. Thirteen subjects then sprayed a 30-ppm formaldehyde solution in an axilla on a double-blind, controlled, 2-wk-use test. Their responses to 30 ppm aqueous formaldehyde indicate that levels below this concentration should be tolerated by sensitive subjects if repeatedly applied to normal skin. Popular formaldehyde-releasing preservatives can be above or below this threshold-eliciting response.
mesh_terms: D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D004361:Drug Tolerance; D005557:Formaldehyde; D006801:Humans; D006968:Hypersensitivity, Delayed; D009824:Ointments; D010328:Patch Tests; D012882:Skin Tests
chemical_list: D009824:Ointments; D005557:Formaldehyde