The most common reaction is a skin rash at the site of contact. In some sensitized people dermatitis may develop at a site away from the site of contact. For example, hand eczema is fairly common among people sensitized to nickel. Less frequently, some people who are sensitive to nickel have asthma attacks following exposure to nickel. People who are sensitive to nickel have reactions when nickel is in contact with the skin, and some sensitized individuals react when they eat nickel in food or water, or breath dust containing nickel.
More women are sensitive to nickel than men.
This difference between men and women is thought to be a result of greater exposure of women to nickel through jewelry and other metal items. People who are not sensitive to nickel must eat very large amounts of nickel to suffer adverse health effects. The most serious effects of nickel, such as cancer of the lung and nasal sinus, have occurred in people who have breathed nickel dust while working in nickel refineries or in nickel processing plants. The levels of nickel in the workplace were much higher than background levels. The Department of Health and Human Services has determined that nickel and certain nickel compounds may be reasonably anticipated to be carcinogens.