Patch test reactions to metal salts in patients with different types of dermatitis.

Metal allergies can be a clinical problem, especially in atopic individuals. This study is unique and contributes with new knowledge in everyday life skin care of irritant and atopic dermatitis patients. The aim of the study was to determine the frequency of positive patch test reactions to metal contact allergens (potassium dichromate, cobalt chloride, nickel sulfate, white mercury precipitate) in patients diagnosed with allergic contact dermatitis, irritant contact dermatitis, and atopic dermatitis. Between 2007 and 2011, patch testing was performed in 2185 patients according to the International Contact Dermatitis Research Group technique. Study results showed statistically significant differences in patch test responses to 2 allergens, nickel sulfate (χ(2)=24.22; p<0.001) and cobalt chloride (χ(2)=22.72; p<0.001). Nickel sulfate was the most common allergen in allergic contact dermatitis and atopic dermatitis, while for irritant contact dermatitis the most common allergen was cobalt chloride. Among the 4 tested metal allergens, the most common and relevant was nickel sulfate (χ(2)=17.25; p<0.004), found in almost all study subjects. In conclusion, the increased awareness of allergens and their potential sources may help limit the use of these chemicals in consumer product manufacturing.