Abstract

Almost everyone in industrially developed countries may be in daily contact with nickel. On the other hand, nickel is a strong biological sensitizer, and its direct contact with the skin may induce delayed hypersensitivity reaction (type IV immune response). Nickel released from jewellery, keys, frames of glasses, and ubiquitous metal accessories of clothing cause allergic contact dermatitis in nickel-sensitized individuals. In our clinic, patch testing with 5% nickel sulphate was performed in 833 patients with dermatitis; the overall frequency of nickel positive tests was 16%. At the same time, the frequency of nickel allergy in patients with allergic contact dermatitis was 41.3%. In the present review article we discuss the environmental exposure of nickel and reasons for sensitization and for development of allergic contact dermatitis. Severity of oxidative stress in the inflamed and healthy skin, depending on the duration of contact dermatitis, is also dealt with.