Occupational conjunctivitis associated with type IV allergy to methacrylates

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 TV allergy to MAS was supported by the following observations: 1) sensitization to several MAS including methyIMA, 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