Allergic contact dermatitis from non-diglycidyl-ether-of-bisphenol-A epoxy resins

In addition to previously presented patients with allergic contact dermatitis from cycloaliphatic epoxy resins (ERs), during 1974-1990, we have seen 4 patients with allergic contact dermatitis (ACD) caused by products containing uncured non-diglycidyl-ether-of-bisphenol-A ER. The patients were negative on patch testing with the standard ER based on diglycidyl ether of bisphenol A (DGEBA-ER). The following non-DGEBA-ERs were included in the causative agents: heterocyclic dimethylhydantoin ER, phenol novolak ER, and brominated ER. We were unable to specify the type of ER in an epoxy primer used by the 4th patient. Apart from the ACD caused by the brominated ER, 1 of the patients also had IgE-mediated occupational rhinitis caused by methyl hexahydrophthalic anhydride (MHHPA), an epoxy hardener. The diagnosis was verified by positive prick tests and specific IgE determinations with MHHPA. Intense rhinitis evoked by a bronchial challenge with MHHPA confirmed the diagnosis. We stress the importance of performing patch testing with the relevant epoxy resins to which the patient has been exposed, in addition to patch testing with the standard ER.