Flare-up at contact allergy sites in a gold-treated rheumatic patient.

Contact allergy to gold sodium thiosulfate and gold sodium thiomalate was established by skin testing in a rheumatic patient intended for gold therapy. An intramuscular test dose of gold sodium thiomalate (Myocrisin) induced a flare-up of previously positive epicutaneous and intradermal test reactions, with a histological and immunohistochemical picture compatible with an allergic contact dermatitis. Since gold allergy is frequent, the cutaneous side-effects of gold therapy ("gold dermatitis") may be explained by such an immunopathological reaction.