Gold trichloride and gold sodium thiosulfate as markers of contact allergy to gold

The usefulness of a trivalent gold salt, gold trichloride (GTC), was evaluated as a marker of contact allergy to gold. Patients patch test-positive or patch test-negative to gold sodium thiosulfate (GSTS), 13 subjects of each, were patch tested with dilution series of GTC and equimolar concentrations of GSTS. In order to avoid false-positive and false-negative test reactions, the salts were buffered and placed on polypropene chambers. Allergic reactions were registered in 9/13 gold-allergic patients with GSTS and in 2/13 with GTC. The sum of positive reactions was 18 with GSTS and 5 with GTC. Irritant reactions were none with GSTS and 2 with GTC in the gold-allergic patients. It is concluded that GTC can elicit positive patch test reactions in patients with gold allergy but to a lesser degree when compared with GSTS. Thus, GTC cannot be recommended in patch testing, and GSTS is still the test agent of choice.