On rare occasions, exposure to
methacrylates (MAs) may induce mucosal symptoms. Three patients, two dental laboratory workers and one
hearing aid laboratory worker, are presented. All three had
allergic contact dermatitis from MAs which disappeared after avoidance of contact with uncured MA compounds. Two of the patients, the dental laboratory assistant and the
hearing aid worker, had also developed symptoms of
conjunctivitis. Both were exposed to chemically curable and light-curable MAs. The association between their
conjunctivitis and type IV
allergy to MAs was supported by the following observations: 1) sensitization to several MAs including methylMA, 2-hydroxyethylMA, ethyleneglycol diMA, triethyleneglycoldiMA, tetrahydrofurfuryldiMA, and 1,4-butanedioldiMA, as well as to
pentaerythritol triacrylate; 2) simultaneous appearance of their eye symptoms and
allergic contact dermatitis; 3) high exposure to MAs because of disturbances of ventilation; 4) disappearance of the eye symptoms during holidays; and 5) opthalmologist's findings of follicular
conjunctivitis with some papillae,
eosinophilia, and
lymphocytosis in conjunctival scrapings corresponding to allergic contact
conjunctivitis. In addition, the activation of eosinophils in the conjunctival scrapings was demonstrated with the
monoclonal antibody technique, and an elevated level of eosinophilic cationic
protein was found in the tear fluid. Our cases suggest that
conjunctivitis may be caused by type IV
allergy to MAs, although type I
allergy (even though prick tests were negative), other
hypersensitivity mechanisms, or irritation cannot be excluded. 4H-Gloves seem to give adequate hand protection even to allergic patients. More attention should be paid to ventilation systems if MA exposure occurs. In some cases, patients with eye symptoms need to be patch tested.