Background: No recent studies reporting nickel sensitivity prevalence in Canadians exist. Objectives: The aim of this study was to quantify nickel sensitivity prevalence in patients at a patch test clinic in Vancouver. Methods: Retrospective chart review of 3263 patients patch tested for nickel sensitivity at our clinic in Vancouver between 2008 and 2020.Results: In total, 24.3% (n = 792 of 3263) of patients were sensitive to nickel. Nickel sensitivity significantly increased over time from 24.3% to 27.9% from 2008 to 2020. Nickel-sensitive patients were significantly more likely to be women ( P < 0.001), between the ages of 19 and 64 years ( P = 0.010), and have dermatitis affecting the face ( P = 0.001) and hands ( P = 0.001). Nickel-sensitive patients were significantly less likely to be 65 years or older ( P = 0.001) and have dermatitis affecting the legs ( P = 0.002). Approximately half of nickel-sensitive reactions were new positive reactions at the second reading.Conclusions: Nickel sensitivity occurred in approximately one quarter of patients and significantly increased over time. Nickel-sensitive patients were more likely to be women, aged 19 to 64 years, and have dermatitis affecting the face and hands; and less likely to be 65 years or older and have dermatitis affecting the legs.
Capsule Summary• Clinicians should be aware of a significant increase in nickel sensitivity over time in Canada from 24.3% to 27.9% from 2008 to 2020. • In addition, nickel-sensitive patients were significantly more likely to be women, between the ages of 19 and 64 years, and have dermatitis affecting the face and hands; and significantly less likely to be 65 years or older and have dermatitis affecting the legs.• Further, approximately half of nickel-sensitive reactions were new positive reactions at the second reading, reinforcing the importance of delayed readings in determining nickel sensitivity.A llergic contact dermatitis (ACD) is a type IV delayed hypersensitivity reaction characterized by pruritic erythematous macules, patches, papules, vesicles, or bullae presenting approximately 48 hours after exposure to an allergen in susceptible individuals with previous sensitization. [1][2][3] Patch testing is the standard for diagnosing causative allergens responsible for ACD. 4 Patch testing attempts to recreate, in vivo, an allergic reaction to nonirritating concentrations of an allergen suspended in a vehicle, aiming to identify a chemical or chemicals that can be removed from the patient's environment, resulting in clearing of an ACD, which may have been present for years. 4 Nickel, a ubiquitous metal used in a wide range of industrial and household products, is the most common contact allergen among metals. Exposures occur through cell phones, body piercings, and stenting procedures to name a few. 5 Nickel allergy is currently the most common cause of contact dermatitis in the industrial world, particularly affecting women. [6][7][8][9][10][11] In fact, nickel allergy is on the rise in the United States, an increase larg...