[Oral nickel provocation and a nickel-free diet. Indications and practical implementation].

In spite of some unsolved questions, an influence of orally ingested nickel on some forms of chronic eczema is generally accepted. In cases of chronic relapsing dermatitis with typical location, positive nickel patch test and positive oral nickel challenge, a nickel-restricted diet may be recommended for a limited period of time. Regional nutritional habits should be considered in the design of diets. Indications, practice and evaluation criteria for oral nickel challenge and nickel-reduced diets are described.