[Nickel risk in metal processing workers. Highlights on toxic and allergic effects].

Nowadays nickel is a global problem, related to occupations (mainly metalworkers) and to life habits. The dietary intake, more than environments, is the source of a basic immune identification and also of possible complications after occupational inhalation or contact. Nickel insoluble compounds are proved to be cancerogenic. Nickel ions are very reactive with proteins and oxidant, then also potential irritant for the airways. Metallic nickel and soluble compounds are sensitizers, causing dermatitis, rhinitis and asthma. Recently a Systemic Nickel Allergy Syndrome (SNAS) has been identified in allergic subjects, with a clinical picture of urticaria, general hitching, headache, gastrointestinal troubles. SNAS may affect allergic occupational or non-occupational ones. Studies are in progress aimed to an oral treatment inducing immunotolerance. Nickel in urine seems to be the best tool for monitoring nickel absorption.