OCCUPATIONAL ALLERGIC CONTACT-DERMATITIS CAUSED BY MERCURY AND BENZOYL PEROXIDE

Occupational allergic contact dermatitis from metallic mercury has sel dom been reported. Here we present two cases of occupational contact d ermatitis from mercury. The first patient was Ct chemistry student who during her practical laboratory work course sed to mercury acetate. S he was also exposed to metallic mercury which was the final product of the chemical reaction. Within about three weeks of exposure she devel oped a vesicular hand dermatitis. Patching testing revealed allergy to both metallic mercury and mercury salts. The second patient was a den tist with occupational mercury allergy from amalgam which had develope d from handling uncured amalgam without protective gloves. The patient had positive patch test reactions to metallic mercury (0.25%-1% in pe trolatum), but not to 0.5-10% amalgam in petrolatum. It has recently b een suggested that 5-10% powder in petrolatum should be used for diagn ostic patch testing of metallic mercury allergy. Our case indicates th at self-made amalgam powder in petrolatum may have a low bioavailabili ty and may not be reliable for patch testing. The dentist also had an allergic patch test reaction caused by benzoyl peroxide, probably from work with dental resins.