Many ear piercing systems pierce ears with earring metals that may have very high Nickel content. For years, the jewelry industry has studied worldwide health trends, consumer preference and comfort. A rising trend of metal allergies from various types of earrings with high Nickel content has been noted. Many people have reported feeling discomfort after wearing earrings and other jewelry for a short period of time. Nickel content in metals has been identified as the most common cause.