A SINGLE ACCIDENTAL EXPOSURE MAY RESULT IN A CHEMICAL BURN, PRIMARY SENSITIZATION AND ALLERGIC CONTACT-DERMATITIS

It is known from experimental studies that antigenic potency and the c oncentration of antigen determine whether exposure to an antigen will result in sensitization. A single accidental exposure to concentrated antigen may therefore induce primary sensitization. The purpose of thi s report was to collect clinical cases in which a single exposure had resulted in contact dermatitis suspected to be allergic. Only patients without previous relevant skin symptoms were included. Patch testing was used to demonstrate sensitization. 6 patients developed occupation al allergic contact dermatitis from accidental exposure. Patch testing revealed allergy to diglycidylether of bisphenol A epoxy resin, polyf unctional aziridine hardener, methyl acrylate, phenol-formaldehyde res in, and methyl-chloroisothiazolinone/methylisothiazolinone (Kathon LX) , respectively. Furthermore, 2 patients developed allergic contact der matitis from their first exposure to tear gas chemicals, namely omega- chloroacetophenone and ortho-chlorobenzylidene malonitrile. A single e xposure can therefore induce both sensitization and subsequent allergi c contact dermatitis without further exposure. The allergens described must be considered strong allergens. The skin should immediately be c leaned if an accidental splash with such an allergen has taken place.