Allergic Contact Dermatitis to Epoxy Resin in Microscopy Immersion Oil: Cases From Canada

Abstract

The presence of epoxy resin in a reformulated immersion oil for microscopy has caused an epidemic of occupational contact dermatitis in laboratory technicians from some European centers. We report 6 additional cases, the mode of presentation of which was similar to the European patients. All patients were patch tested to the undiluted oil, and some were tested to the European or North American standard series and to an extensive series of glues and adhesives allergens. At 96 hours, all 6 patients displayed a strong 2+ to 3+ reaction to the undiluted oil. Two patients were not further tested, but in the remaining 4, positive reactions were seen to epoxy resin from the standard tray. One patient reacted to cycloaliphatic epoxy resin, and 2 displayed positive tests to the reactive diluents phenyl glycidyl ether and cresyl glycidyl ether. These further cases confirm the strong sensitizing properties of this particular immersion oil. The product, manufactured by Leica Microsystems (Wetzlar, Germany), since has been withdrawn from sale.

Active sensitization by epoxy in Leica® immersion oil

“…The final concentration of the strongest allergen should usually not exceed that of commercial patch test series or the concentration otherwise recommended (18). The Leica ® immersion oil has elsewhere been patch tested as is (4, 8) or at 50% (1). Accordingly, the final‐patch test concentration clearly exceeds the concentration generally recommended for epoxy resins (17, 18), and this induced active sensitization in our patient.…”

“…Accordingly, the final‐patch test concentration clearly exceeds the concentration generally recommended for epoxy resins (17, 18), and this induced active sensitization in our patient. In previous studies in which strong immersion oil has been used for patch testing (1, 4, 8), the patients had already been occupationally sensitized to at least 1 epoxy compound, and therefore active sensitization did not necessarily occur. However, it cannot be excluded that the patients in these studies were sensitized to other epoxy compounds to which initially they were not allergic.…”

“…A Leica ® immersion oil containing epoxy resins (Table 1) caused a worldwide epidemic of allergic contact dermatitis in the late 1990s (1–11). In many clinics, the patients’ own immersion oil was tested as is, which carried the risk of active sensitization.…”

“…Eventually, it was shown that at least some of these patients (11) had been sensitized by a Leica ® immersion oil. A 35‐year‐old female laboratory technician, however, had had mild hand dermatitis, together with dermatitis on her face and neck (4, 8). She had been patch tested elsewhere with the immersion oil as is.…”