Iron earrings are allergic, and silver earrings are safer. If it is a new ear hole, it is recommended to use gold earrings. One in every 6,543.8+million people in the world is allergic to metals. The most common allergic metal is nickel, and jewelry is also the main source of allergies. Once an allergy occurs, it will cause contact dermatitis such as redness, itching and yellow water flowing around. Many alloy products in daily life contain nickel. Coins, various alloy products, electroplated materials, spectacle frames, metal watch belts, belt buckles, artificial jewelry, underwear buckles, etc. Direct contact with the skin can cause allergies in sensitive people. Chromium, mercury, gold, platinum and barium can also cause allergic reactions, such as dampness and anaphylactic shock, which are all adverse reactions caused by the release of metal ions. Perforation is a kind of trauma to human body. Putting metal foreign bodies that do not belong to human tissue into the wound site will cause continuous stimulation to the human body, make the perforation site thicker, the tissue may proliferate and appear tumor-like processes, and even become cancerous in severe cases. Perforation of nerve endings such as nose, lips and tongue with ornaments will affect the function of organs to some extent.