TRUE test panel which includes gold sodium thiosulphate (GSTS), 1 % w/v in petrolatum, and gold microparticles, 20-micron diameter, 1 % w/v in petrolatum, will be added added to the baseline series. It will be applied to the upper back of healthy adults in aluminum Finn Chamber for 48 hours. Clinical evaluation will be performed 24 hours after removal the test according to standard procedures for evaluation of epi-cutaneous challenging (Johansen 2015).
The investigators hypothesize gold is inert and thereby there is no pure-gold allergy. The primary aim of this study is to measure the prevalence of allergy to metallic pure gold microparticles and allergy to GSTS.