Skin allergies to metal fall under the category of allergic contact dermatitis. If you have allergic contact dermatitis, it means that your immune system over-reacts when your skin touches certain substances. The symptoms of such over-reactions can include rashes, redness, swelling and pain. With long-term exposure to certain allergens, your skin might darken and become leathery and cracked in specific areas. While people can develop allergies to a number of types of metal, the most common by far is an allergy to nickel. In fact, nickel allergies are the most common type of allergic contact dermatitis in the world.

Most commonly, people notice nickel allergies where they wear jewelry like earrings, rings and necklaces. Allergic people who work with nickel-containing products, like hairdressers, caterers and metalworkers, also notice reactions on their hands. Nickel alloys are used to create a whole slew of everyday items, like buttons, buckles, zippers and kitchen utensils. Nickel is also found in some 14K and 18K gold, and when you sweat, it draws the nickel out. Stainless steel has nickel in it, too, but it's usually bound so tightly that it won't affect even the most allergic person. But very allergic people can react to the nickel present in some food items, which include nuts, chocolate, tea, coffee, beer and apricots.

If you're allergic to nickel and you're sweating, you can start feeling an itchy allergic reaction within 15 minutes of touching a nickel-containing product. However, if you're not sweating, you may not react for a few hours. After a day or two, you'll probably notice a rash. The best way to avoid nickel-caused allergic contact dermatitis is to avoid products with nickel. Your dermatologist can give you a kit so that you can test various items for nickel, and there are also sprays available that you can use to coat nickel items to prevent them from actually touching your skin. Clear nail polish works, too.