Patch-test reactions to plastic and glue allergens

Plastics and glues are common causes of occupational dermatoses, but only f eu reports have dealt with patch-test reactions caused by plastic and glue allergens. Patients exposed to plastics and remitted to an occupational der matology clinic, were patch-tested with 50-53 plastic and glue allergens du ring a 6-year period. Conventional patch-test techniques Here used. The mos t common causes of allergic patch-test reactions in 360 patients were novol ac epoxy resin (5.1%), phenol formaldehyde resin (3.1 %), 4-tert-butylcatec hol; (2.68), phenyl glycidyl ether (2.6%), diaminodiphenyl methane (2.2%), benzoyl peroxide (2.2%), hexamethylene tetramine (2.0%) and o-cresyl glycid yl ether (1.6%). The allergens that most often elicited irritant patch-test reactions were: benzoyl peroxide (9.5%), abitol alcohol (3.6%), hydroquino ne (3.1%), acid-catalyzed phenol formaldehyde resin (2.5%) and toluene diis ocyanate (1.9%). Twenty-sis out of 53 chemicals caused no allergic reaction during the 6-year period. Plastic: allergens in the standard series provok ed allergic reactions with formaldehyde (5.8%), diglycidyl ether of bisphen ol ri (3.2%), 4-tert-butylphenol-formaldehyde de-resin (1.1%), toluene sulp honamide formaldehyde-resin (1.1%) and triethylenglycol diacrylate (0.4%). Although half of the plastic chemicals gave no allergic patch-test reaction s during a 6-year period, with unusual allergens this low yield needs to he accepted, because otherwise rare allergies,will not be detected. Also a ne gative reaction has diagnostic value.