Does gold concentration in the blood influence the result of patch testing to gold?

BACKGROUND: We have recently found a correlation between contact allergy to gold sodium thiosulphate (GSTS) and gold concentration in the blood (B-Au) in a stented population: the higher the B-Au, the stronger the patch-test reaction. OBJECTIVES: To further investigate the correlation between B-Au and patch-test reactivity to gold. METHODS: In this provocation control cross-over trial of 24 patients with dermatitis with a known contact allergy to gold, the patients were randomized into two groups where one was topically provoked to gold (15 mg GSTS) and one to the control. All patients were simultaneously patch tested with GSTS in 10 aqueous dilutions (1.1 mg GSTS). Patch-test readings were performed and blood was drawn. After 6 weeks, the experiment was repeated and the group that had previously been provoked with gold was now provoked with the control and vice versa. RESULTS: B-Au was higher after gold provocation whereas no treatment effect was discerned for minimal eliciting concentration (MEC) or summarized test score (STS). Instead, significant differences in period effect were observed implying higher B-Au and STS and lower MEC on test occasion II. The most likely explanation is the increased B-Au and /or booster effect from test occasion I. There was a correlation between B-Au and MEC: the higher the B-Au, the lower the MEC. CONCLUSIONS: The correlation between B-Au and MEC indicates that the B-Au is of importance for the skin reactivity to gold.

High frequency of contact allergy to gold in patients with endovascular coronary stents.

BACKGROUND: Stent implantation is an effective method for treatment of atherosclerotic disease. Factors predisposing to in-stent restenosis are still largely unknown. Contact allergy to metal ions eluted from the stent has been suggested to be a risk factor. OBJECTIVES: To explore whether there is a possible induction of contact allergy to metals used in stents among patients with a stainless steel stent containing nickel (Ni stent) and patients with a gold-plated stent (Au stent). METHODS: Adults (n = 484) treated with coronary stent implantation participated in the study with patch testing. The study design was retrospective and cross-sectional with no assessment of contact allergy before stenting. Age- and sex-matched patch-tested patients with dermatitis (n = 447) served as controls. RESULTS: Of Au-stented patients, 54 of 146 (37%) were allergic to gold compared with 85 of 447 (19%) controls (P < 0.001). Within the stented population there were no statistically significant differences in contact allergy to gold or nickel between Ni-stented and Au-stented patients. In multivariate models where other risk factors for contact allergy to gold were considered, the Au stent showed a trend towards statistical significance (odds ratio 1.43, 95% confidence interval 0.95-2.16; P = 0.09). CONCLUSIONS: As the frequency of contact allergy to gold is higher in stented patients independent of stent type it suggests a previous sensitization. However, several pieces of circumstantial evidence as well as statistical analysis indicate the possibility of sensitization in the coronary vessel by the Au stent. Ni stents and Au stents should not be ruled out as risk factors for induction of contact allergy to these metals.