Is There an Allergy to Pure Metallic Gold Micro‐Particles?—An Epicutaneous Study of Gold Micro‐Particles, Gold Thiosulphate, and Placebo

Background Previous studies investigating gold allergy have used gold thiosulphate (GCST) rather than pure gold, reporting an incidence up to 30%. Objectives As it is unclear whether these reactions are due to ions from pure gold or solely to ions from gold salts, this study aimed to determine whether an allergy to pure gold itself exists. Materials and Methods Sixty patients with cutaneous allergic reactions participated in the study. A standard epicutaneous test was performed with both a test chamber with pure gold micro‐particles (20–40 μm in diameter) in petrolatum and the GST, which is part of the standard ‘Thin Layer Rapid Use Epicutaneous Patch (T.R.U.E.) Test’. Results None of the patients reacted to the gold micro‐particles, while thirteen reacted to GST. Conclusions The study did not elicit any allergic reaction to the gold micro‐particles. These findings confirmed clinical observations that allergy to gold salts is quite common but suggest that pure metallic gold is not an allergen.