A Casse of Systemic Lichen Planus due to Mercury in Dental Amalgam

A 4-year-old boy with white enanthema on his lower lip and buccal mucosa and pigmented macules on his face, buttocks and lower extremities visited our clinic in March 28, 1989. He had metal dentures and plugged carious tooth with amalgam in May, 1988. In July, 1988, he noticed white macules on his lower lip and buccal mucosa. He also noticed pigmented macules after plant dermatitis on his buttocks and insect bites on his lower extremities. Gradually several pigmented spots appeared on his face and ears. Histological feature of the lesion on the leg was lichenoid reaction. And histology of the buccal mucosa was typical lichen planus showing liquefaction degeneration of basal layer and band like round cell infiltration in upper dermis. We performed patch testing 19 kinds of dental metales. Only HgCl2 0. 05% aq. showed allergic reaction. The fluorescence X-ray analysis showed a large amount of mercury in amalgam. The white macules on his lower lip and buccal mucosa and pigmented macules on his face had become less distinct during 4 months after removing amalgam from his carious tooth. From the above matters, we dianosed his eruptions as lichen planus caused from allergic reaction to mercury in dental amalgam.