Pruritic rash
Each of these 5 patients had a pruritic rash. The locations varied: face, ears, wrist, and waist. But the cause was the same.
Nickel dermatitis is increasingly common
Nickel is a leading cause of allergic contact dermatitis and is responsible for more cases than all other metals combined.1,2 The incidence of nickel dermatitis has been increasing in the United States for the last 15 years, annually affecting an estimated 14% to 20% of women and 2% to 4% of men.3,4 The higher percentage in women is related to nickel exposure associated with ear piercing and nickel-plated jewelry. In fact, the highest risk for nickel allergy is in young females with pierced ears.2,5,6 The number of affected males, however, is increasing, as earrings and body piercing gain popularity in this group.3
Certain occupations with high exposure to nickel, such as cashiers, hairdressers, metal workers, domestic cleaners, food handlers, bar workers, and painters, are also at risk for acquiring nickel dermatitis.7 Patients with atopic eczema are also at increased risk.8,9
Sweating may increase the severity of the dermatitis. Sodium chloride in the sweat causes corrosion of the metal and increases nickel exposure.10 Nickel release is therefore common in areas of the body that tend to be sweaty—for example, the hands, especially around the fingers, where inexpensive rings containing nickel are worn, or on the hands of individuals who carry metal key rings.
Consider oral intake of nickel, too. Another far less common, but important, nickel allergy presentation is systemic contact dermatitis from oral intake of nickel. Nuts, legumes, and chocolate can cause a flare-up reaction in a previously positive patch test site or previous site of nickel dermatitis.11 Patients can also develop a dyshidrotic eczema on the hands. Itching and general symptoms, such as headache, nausea, and malaise, have also been reported after the oral nickel exposure of nickel-sensitive individuals.12 Dietary intervention studies indicate that it is possible to reduce the activity of dermatitis in these patients by maintaining a diet low in nickel.13-16
Finally, severe local reactions to nickel and other contact allergens can lead to auto-eczematization, in which a papular or papulosquamous eruption and pruritus appear distant from the site of exposure.
