Nickel contamination of gold salts: link with gold-induced skin rash

Intramuscular chrysotherapy is a well-established treatment for rheumatoid arthritis. Its therapeutic use has been limited by the high incidence of dermatological side-effects. The pathogenic mechanisms of these are unknown, but could include allergic reactions to gold or to nickel contaminating the gold. In order to investigate these mechanisms further, 15 patients, who developed cutaneous eruptions after chrysotherapy, were assessed using skin biopsy and lymphocyte transformation stimulated by gold and nickel salts in vitro. Chrysotherapy induced two main cutaneous eruptions: lichenoid reactions and non-specific dermatitis. Peripheral blood mononuclear cells from patients with lichenoid reaction proliferated to gold salts in vitro, while those who developed non-specific dermatitis responded mainly to nickel. Nickel was a significant contaminant of the gold preparation (sodium aurothiomalate, Myocrisin, Rhone-Poulenc Ltd), amounting to a total of 650 ng after 6 months treatment. We suggest that a significant percentage of skin reactions during chrysotherapy are due to nickel contamination of the gold preparation.