Contact Urticaria Testing at a Specialized Contact Dermatitis Clinic: Our Experience Over 5 Years

Background: Distinguishing between contact urticaria and allergic contact dermatitis can be challenging, and some patients may exhibit a combination of immediate and delayed-type reactions. Patients with suspected contact allergy are often referred to specialized patch testing centers, some of which may not offer contact urticaria testing.Objective: To examine the role of contact urticaria testing at our institution, specifically analyzing its ability to unveil reactions not detected during standard patch testing.Methods: Retrospective study of 2,396 patients comprehensively patch tested over a 5-year period. For each allergen in our contact urticaria series, positive reactions were assessed for concordant reactions on standard patch testing. A separate analysis including cross-reactors was conducted for fragrance and benzoate allergens.Results: Of 31 patients who received both contact urticaria and standard patch testing, 24 exhibited at least 1 positive contact urticaria reaction, amounting to 73 total reactions. 86% (63/73) of these reactions were identified with contact urticaria testing only.Conclusions: In our experience, contact urticaria testing revealed reactions not demonstrated during standard patch testing. Standardized contact urticaria testing protocols may result in improved diagnosis and disease clearance. Thus, patch testing centers might consider performing contact urticaria testing for patients with immediate-onset symptoms.