Piercing and Metal Sensitivity: Extended Analysis of the North American Contact Dermatitis Group Data, 2007-2014

Background: Body piercing provides a unique route of metal exposure. Objective: The aim of this study was to update previous analyses using the North American Contact Dermatitis Group data comparing pierced and unpierced individuals. Methods: This was a retrospective cross-sectional analysis of 17,912 patients patch tested by the North American Contact Dermatitis Group from 2007 to 2014 for demographics, positive reactions to metals (nickel, cobalt, chromium), and detailed analysis of nickel reactions by age, sex, and source of exposure. Results: Piercing was significantly associated with female sex, being older than 18 years, and atopy (P < 0.003). Nickel sensitivity was associated with 1 or more piercing for men and women combined (P < 0.0001; relative risk [RR], 2.54; 95% confidence interval [CI], 2.35-2.75), although this association was stronger for men (RR, 2.21; 95% CI, 1.77-2.76) than women (RR, 1.47; 95% CI, 1.31-1.65). The frequency of positivity to nickel increased with number of piercings (14.3% for 1 piercing to 34.0% with ≥5 piercings). Piercing was not significantly associated with cobalt sensitivity alone (P = 0.8992) and was negatively associated with chromium sensitivity (P < 0.0001). Jewelry was the most common source of allergic reactions to nickel irrespective of sex or pierced status. Conclusions: Nickel sensitivity was significantly associated with piercing in both men and women. Jewelry was the most common source.