Nickel contact allergy and a nickel-restricted diet.

More than half of nickel-allergic patients develop secondary eruptions, that is, dermatitis in areas of the skin that are not in obvious contact with nickel-plated items. Similar eruptions occur after placebo-controlled oral challenge with inorganic nickel salts. The possible relationship between ingestion of nickel in food and secondary eruptions in nickel-sensitive patients is discussed, making reference to the available literature. Recommendations are given for the management of patients suspected to have nickel dermatitis aggravated by nickel in food.