[Contact allergy to gold and its alloys. Pertinence of gold salt patch tests].

Allergic contact dermatitis to gold and its alloys is a rare affection and it is difficult to interpret gold salts patch tests. We report two cases of patients with positive patch tests to 0.5% sodium aurothiosulfate discovered during a dermatology exploration of an occupational contact eczema (for the first patient) and an intolerance to gold jewelry (for the second). There is much confusion in the literature concerning the allergologic exploration of contact dermatitis to gold: no standardized test, possible cross reactions between different gold salts, the tests often irritate. The mechanism of sensitization to gold salts is unknown since pure gold is inalterable and does not contain any salts. The pertinence of a positive test to one or more gold salts must therefore be examined carefully and the diagnosis of gold allergy must not be made without sufficient evidence.