Sensitivity to nickel has been increasing over time. The government in certain countries is monitoring the metals used for body piercing. Irrespective of whether you are sensitive to a certain metal or not, it is always better to use hypoallergenic metals for body piercing in order to avoid any allergic reaction. Hypoallergenic metals do not give rise to any allergic reaction and thus the piercing heals faster, putting less stress on the immune system. In fact, before undertaking the piercing, the piercer should inquire if you are sensitive to any metal. Many customers are not even aware of the fact that they are sensitive to a certain metal. Sometimes, the customer does not even know what metal is being used for the piercing. Frankly, both the piercer and the customer are responsible for avoiding the use of a metal that the customer is allergic to. The piercer should ask the customer about his sensitivity before proceeding with the piercing. However, if the customer has ever had a skin problem due to the use of a particular metal, this fact should be informed to the piercer. If you get skin irritation with wearing metal-backed wristwatches, metal buttons in jeans or belt buckles, you might have an allergy to nickel, which many people have. According to a European directive, jewelry used initially in a piercing should not contain more than 0.05% nickel. Once the piercing heals, jewelry with a slightly higher percentage of nickel might be used. Nickel-free surgical steel is ideal for initial use in the piercing as it is graded 316L and contains less than 0.01% nickel. The percentage of nickel in 'common' surgical steel is more than 10%. Using Surgical Implantation grade Titanium of the grade 6A1 4V to BS7252 and Niobium in piercings that are new is safe because these metals do not lead to any reactions in the human body. Sometimes, titanium is colored in such a way that no undue reactions are caused. However, the color might fade with time. Silver is generally mixed with other metals like nickel, due to which its use should not be made in the initial stages. 9 carat gold and other low grades of gold have several other metals mixed with them, due to which their use in a new piercing should be avoided. High grade gold such as 24 carat gold is used for making jewelry for occasional use. Pure gold is generally not useful for making jewelry for long-term use because it is very soft. Acrylic jewelry does not usually cause skin irritation, but acrylic jewelry tends to develop breaks easily. This might lead to the development of bacteria and germs. Retainer jewelry that is jewelry made of transperant acrylic in order to make it subdued also poses the same problem. Acrylic jewelry is ideal for temporary use; however, if it is taken care of well and is worn after the piercing heals completely, there are fewer chances of skin problems occurring. PTFE or polytetraflouroethylene is a harmless material that is highly flexible. Many a times, it is used in piercings where hard metal jewelry would lead to rejection on account of the stress at the area. Due to its flexible nature, the stress caused at the area of the piercing reduces and so it accelerates the process of healing of the piercing. In case red and irritated skin develops around the piercing or there is drainage from it or if the area is sore or extremely dry, the user may need to get the jewelry changed to one that is made from biocompatible material.