context: If earrings make your earlobes itch or your necklace leaves a rash around your neck, you may be allergic to nickel. It's one of the most common skin allergies, in part because nickel is used so many things, including jewelry, cell phones, coins, zippers, eyeglass frames, belt buckles, and keys. You'll usually see symptoms 12 to 48 hours after you come into contact with nickel. You may notice itching, redness, rash, dry patches, and swelling of the skin. Sometimes blisters follow. They may break, leaving crusts and scales. If left untreated, your skin may become darker, leathery, and cracked. Most likely, the rash is only on the part of your skin in direct contact with the nickel. In serious cases, the rash may spread. Sweating can make it worse. If your skin becomes infected, it will become warm and redder or filled with pus. Get medical care right away. Your doctor can often diagnose a nickel allergy by looking at your skin and asking if you've touched anything metal. A dermatologist also can give you a skin patch test. She'll put tiny amounts of nickel and other allergens on the skin of your upper back and covers them with patches. The patches must stay on for 48 hours. If you're allergic to nickel, your skin will likely show a reaction after that amount of time. In some cases, you'll need more tests. Once a nickel allergy develops, it often lasts your whole life. But there are ways to ease your symptoms. The most important thing you can do is avoid contact with objects that can cause a reaction. For mild symptoms, a hydrocortisone cream and antihistamine pills you can buy at the drugstore may help. For more severe symptoms, you doctor may prescribe a steroid cream or a drug that works on your immune system. If your symptoms are very severe, your treatment may also include steroids that you take by mouth and antihistamine pills. If your skin is cracked or blistered, you should take off any metal jewelry right away and see your doctor for treatment to avoid getting an infection. 1. If you have your ears or other body parts pierced or tattooed, have it done with sterile, surgical-grade, stainless steel instruments. It's a good idea to avoid piercing guns, since they could contain nickel and can cause bacterial infections. 2. Make sure your jewelry is made of surgical-grade stainless steel or either 14-, 18- or 24-karat yellow gold. White gold may contain nickel. Other nickel-free metals include pure sterling silver, copper, platinum, and titanium. Polycarbonate plastic is okay. If you must wear earrings that have nickel, add plastic covers made for earring studs. 3. Buy eyeglass frames made of titanium or plastic. 4. Choose clothes, including bras and other under-things, with buttons, snaps, rivets, or fasteners that are made of plastic or are plastic-coated or painted metal. If your clothes have nickel items, switch to plastic or plastic coated. 5. Wear watchbands made of leather, cloth, or plastic. 6. If a good piece of jewelry that you wear daily -- such as a wedding ring -- causes a reaction, ask a jeweler about having it plated in a less-allergic metal, such as platinum. 7. If you're extremely sensitive to nickel, you may also need to avoid nickel-rich foods such as mixed nuts and chocolate.