Epoxy resin exposure and dermatitis - a case study : allergies in the workplace

Epoxy resins are a well-known cause of occupational contact dermatitis (OCD). A high index of suspicion for allergic or irritant contact dermatitis in workers dealing with these agents should be maintained. The cases presented below highlight some of the complexities of assessing skin reactions to epoxy resins. Contact dermatitis from epoxy resin exposure. tant reaction fades by 72 hours. For practical reasons the patches were read only once, after 3 days. Patients were instructed to remove the patches if they developed a severe reaction before the second visit and to note exactly where the patches had been placed. The reactions are graded as shown in Table I. Results Results are shown in Table II. Clinical presentation A careful work history confirmed that all workers were employed in factories in which epoxy resins were used. All the workers complained of itch and/or a burning sensation of the skin. Eight workers presented with dermatitis (redness, swelling, blistering, weeping, scaling and thickening of the skin). One worker presented with swelling and redness of his eyes and lips which was typical of urticaria. The tenth worker presented with patchy loss of pigmentation known as leucoderma. The distribution of the rash, namely on the hands, arms, neck, body and face suggested that the workers were exposed to dusts and vapours containing the sensitising agents, as well as known direct skin contact. Patch testing • Four of the workers had definite reactions (1-2+) to epoxy resin included in the European standard series. This confirmed true allergy. • A further 3 workers had questionable reactions (? ) to the same allergen, indicating possible allergic reactions. Workers were also tested with relevant allergens from the plastic and glues series but these were negative. • Four of the workers reacted to epoxy-based substances from the workplace. • One of the workers developed mild irritant reactions to workplace substances. • Worker No. 7 complained of swelling of the eyes and lips immediately after entering the workplace area which is consistent with an acute urticaria. • Worker No. 9 presented with leucoderma (resembling vitiligo) around the eyes and on the neck. DISCUSSION From the results it can be seen that exposure to epoxy in these workers caused occupational contact irritant and allergic dermatitis, urticaria and leucoderma. Symptomatic workers who are exposed to epoxy resins should be assessed by means of a detailed medical work and exposure history, a medical examination and comprehensive allergy testing. The most common skin reaction in these workers was contact dermatitis which is known to be the most common form of occupational skin disease (OSD). In the cases considered in this study half of those tested had definite reactions to epoxy resins while three others had equivocal reactions. This corresponds with other studies that indicate that epoxy resin is a common cause of ACD. The questionable reactions indicated possible sensitisation and these workers should be monitored and retested if indicated. In addition to the ESS the appropriate allergens from the plastic, glues and epoxy series were applied but these were negative. In the newer epoxy series (Chemotechnique) additional allergens have recently become available. These are important as it has been shown that polyamine hardeners such as diethylenetriamine, triethylenetetramine and dimethyloamino propylamine, as well as reactive diluents can also cause allergic reactions. Therefore potential reactions in patients who may have been allergic to these epoxy chemicals were not detected. It is hoped that the NIOH will shortly acquire these allergens. In addition positive reactions may have been missed since reactions occasionally occur up to 6 to 7 days after application of the patch test. This case study highlights the importance of testing with workplace agents and confirms the findings of other studies. In one case the worker tested negative to the epoxy allergens in the commercial series but positive to the workplace substance. In another case epoxy resin allergy was confirmed by a positive reaction to the allergen supplied by the workplace. The composition of workplace agents may not be identical to the commercially available allergens because of manufacturing variations and different formulations. Tests with workplace substances, however, are problematic as false-negative and false-positive reactions may occur. The substance may be inappropriately diluted or may contain other irritating constituents. Epoxy resins and many other chemicals used in the workplace (e.g. thinners, mica, and solvents) may cause irritant reactions in workers. Since patch tests identify allergic reactions and are not useful in the detection of irritant reactions the possibility of irritant reactions should be considered in all cases. In the cases described above many workers used thinners to remove cured epoxy from their hands. In an attempt to remove cured epoxy one worker resorted to using sandpaper. Worker No. 7 complained of an almost immediate swelling of the eyes and lips when entering the work area. This is typical of an urticarial type of response (probably IgE-mediated hypersensitivity reaction). Urticarial reactions are rare but do occur in epoxy-resinexposed subjects, normally in conjunction with ACD. This IgE type of reaction is important since it can lead to other occupational disorders such as rhinitis, conjunctivitis and asthma. An unexpected finding was a case of leucoderma (resembling vitiligo) around the eyes and on the neck of worker No. 9. Several such cases following allergic contact dermatitis to epoxy resin have been documented. Occupational health workers in companies where epoxy resins are used should be aware of this condition. Since epoxy resin exposure is a common cause of OCD, it is important that the work environment is well controlled and the workers properly protected. The reactions on the face and neck seen in some of the workers demonstrate the importance of vapours and possibly dusts in causing OCD. 40 Current Allergy & Clinical Immunology, March 2008 Vol 21, No. 1 Table I. Interpretation of patch test reactions Grade Reaction Appearance – Negative Normal ? Questionable Erythema 1+ Weak Non vesicular with erythema and papules 2+ Strong Vesicular or oedematous 3+ Extreme Spreading, bullous or ulcerative IR Irritant Glazed, ‘burned appearance’, pustular, edge effect