Background: Metallic allergens such as nickel are among the most common causes of allergic contact dermatitis (ACD), but frequencies of contact dermatitis to these allergens may vary in different areas.
Objectives: This study aimed to determine the frequencies of ACD caused by three common metallic allergens: nickel sulfate; potassium dichromate; and cobalt chloride.
Methods: Data for 1137 patients with clinical diagnoses of contact dermatitis and/or atopic dermatitis evaluated by patch testing in Iran during a 5-year period were retrospectively studied to establish the frequencies of hypersensitivity to these metallic allergens.
Results: A total of 313 patients (27.5%) gave positive patch test results for at least one metallic allergen. Allergy to nickel (229 cases, 20.0%) was the most commonly observed, followed by allergy to cobalt (90 cases, 8.0%) and allergy to chromium (70 cases, 6.2%). Nickel allergy was significantly more frequent in females and in subjects aged <40 years, whereas chromium hypersensitivity was more common in males and in subjects aged >40 years. Sensitivity to nickel or chromium was a risk factor for cobalt allergy.
Conclusions: Nickel was most commonly identified as a metallic allergen in Iran and tended to affect women aged <40 years. Regulations pertaining to nickel release may decrease the frequency of nickel hypersensitivity in Iran.
© 2013 The International Society of Dermatology.