Nickel-induced allergy and contact dermatitis: does it induce autoimmunity and cutaneous sclerosis? An experimental study in Brown Norway rats.

Nickel sensitization is a growing problem and the most common cause of allergic contact dermatitis. The aim of this study was to investigate whether nickel chloride can induce autoimmunity and cutaneous sclerosis in immunosensitive rats. Nickel chloride, in a dose of 4.5 mg in 0.2 ml NS, was administered by the oral and subcutaneous routes to 20 Brown Norway rats. Autoantibodies (ANA, anti-RNP, anti-SCL70 and anti-centromere) were measured and compared in pre- and post-challenge serum samples. Histological studies were also performed in skin biopsies obtained from six positively responding rats and compared with an equal number of control rats at the 14th week post-challenge. Serum ANA was high in a significant number of rats in both the oral (P < 0.005) and subcutaneously nickel-treated groups (P = 0.02), while the anti-SCL70 was high in a significant number of rats in only the orally nickel-treated group (P = 0.04). Histologically, subcutaneous and oral nickel-treated groups showed sclerodermic features of the skin (P = 0.22, P = 0.5), respectively. It may be concluded that nickel chloride can induce scleroderma-related autoantibodies and cutaneous sclerosis. More prolonged duration of exposure is probably associated with greater risk. This is the first study showing the potential risk of nickel in triggering the development of cutaneous sclerosis in susceptible hosts.