Chrysiasis: the role of sun exposure in dermal hyperpigmentation secondary to gold therapy.

To investigate the role of sun exposure in the pathophysiology of chrysiasis, we studied 10 Caucasian female patients with rheumatoid arthritis: 4 with clinically apparent chrysiasis and 6 without apparent pigmentation. Three patients without chrysiasis had received over 4 g of gold and 3 less than one g. The mean melanin score, determined by histological examination of sun exposed and nonsun exposed skin, was significantly higher in the sun exposed skin of the chrysiasis and high dose controls than low dose controls (p less than .05). Concentration of gold measured semiquantitatively by transmission electron microscopy and quantitatively by atomic absorption showed increased gold concentration in sun exposed when compared to nonsun exposed skin of chrysiasis and high dose controls (p = .26). Low dose controls had no gold demonstrated by either method. Our results suggest that gold deposition in the dermis stimulates melain production and that melanin is important in hyperpigmentation of chrysiasis. Furthermore ultraviolet light may induce preferential uptake of gold by the skin.