Nickel exposure from keys: a Brazilian issue

Abstract: Keys are a significant source of exposure to metal allergens and can be a relevant problem for nickel-allergic individuals. This study aimed to perform nickel and cobalt spot testing among the 5 most common Brazilian brands of keys. Among the tested keys, 100% showed positive result to nickel spot test, 83,3% presented strong positive reaction. 50% exhibited cobalt release as well. Nickel release from keys is very common in our country and may cause a negative impact on sensitized individual's quality of life. Study's results highlight the importance of establishing directives to regulate nickel release in Brazil.

Disulfiram and low nickel diet in the management of hand eczema: a clinical study.

BACKGROUND: Hand eczema due to nickel sensitivity is a challenging task for the dermatologist. The average human diet provides sufficient amount of nickel, which acts as a provocating factor in nickel-sensitive individuals. When such patients are treated with steroid or other immunosuppressives, only short-term remission is obtained. This is because unless the dietary intake of nickel is minimized and the existing amount of nickel in the body of the sensitized individual is depleted, long-term remission is unlikely. AIM: To evaluate the efficacy of oral disulfiram, a nickel-chelating agent and low nickel diet (LND) in reducing the clinical symptoms and preventing frequent relapse of hand eczema in nickel-sensitive individuals. METHODS: A total of 21 patients with chronic vesicular hand eczema with nickel sensitivity were taken for this study. Patients were randomly divided into two groups: (a) Study group consisting of 11 patients (8 females and 3 males). They were prescribed disulfiram orally for a period of 4 weeks; they started LND 2 weeks prior to initiation of disulfiram therapy and continued till the end of follow-up period. (b) Control (placebo) group consisting of 10 patients (7 females and 3 males). They were allowed to continue with normal diet. Each of them received lactose tablet daily as placebo for 4 weeks. It was a comparative study and participants were not aware if they belonged to study group or control group (single blind trial). RESULTS: Hand eczema healed completely in 10 (90.9%) out of 11 patients treated with disulfiram and LND during the treatment period in the study group, compared with 1 out 10 patients in control (placebo) group (non significant). Mild relapse was noted in 5 patients in between 2-12 weeks of follow-up period. CONCLUSION: Low nickel diet and short course of oral disulfiram therapy can be considered a good option for the control of chronic hand eczema in nickel-sensitive individuals.

Comparative pulmonary toxicity of cadmium and nickel: histopathological and bronchoalveolar lavage analysis.

Pulmonary toxicity of cadmium and nickel was evaluated in rat lungs following intratracheal instillation of their chlorides. Concentration of both the metals varied from 0.2-5 mM. Both the metals increased total number of cells, number of polymorphonuclear neutrophils, total protein, sialic acid and the activity of lactate dehydrogenase and beta-glucuronidase in bronchoalveolar lavage 3 days after exposure. Increase in the levels of the selected parameters was more following Cd exposure than in Ni exposed rats. Histologically there was an inflammatory response and interstitial fibroblastic proliferation in the lungs of Cd exposed animals. These changes were mild in Ni-exposed animals and higher concentrations of Ni were needed to produce changes similar to those produced by smaller concentrations of Cd.

The immunology of nickel-induced allergic contact dermatitis.

Attempts have been made to elucidate the immunopathogenesis of contact allergy; yet, the exact mechanism by which nickel-induced allergic contact dermatitis (NACD) occurs is far from clear and is discussed herein. It seems to suggest that a direct nickel-MHC class II molecule binding on the skin antigen presenting cells such as Langerhans cells (LCs) would result in Th1 cell activation. Substances such as serotonin and cytokines such as TNF-alpha produced by activated mast cells may increase adhesion molecule expression and thus, enhance T cell trafficking in the skin. Cytokines such as IFN-gamma and IL-1 and perhaps IL-12 certainly play a crucial role in the activation of Th1 cells. Along with possible function of CD8 cells, downregulation of NACD may be mediated by suppressed function of LCs via the action of activated keratinocytes-derived IL-10. Inhibition of NACD can also be generated by feeding with nickel, suggesting that the induction of oral tolerance to nickel may be beneficial for an alternative immunotherapy of nickel allergy. Nevertheless, this testable model provides a direction for further investigation.