Frequency and clinical relevance of contact allergy in dental patients

Background: While many studies have reported on occupational allergic contact dermatitis amongst dental personnel, studies on the relevance of patch testing in dental patients are scarce. Objectives: To determine the frequency and clinical relevance of contact allergy in patients with intra- and perioral complaints. Methods: A total of 360 patients with intra- and perioral complaints suspected of having a contact allergy were patch-tested with the dental allergen series, European Baseline Series, and extended Amsterdam Baseline Series at Amsterdam University Medical Centers between January 2015 and November 2021. Results: A total of 285 patients (79.2%) had a positive patch test reaction for either one (18.6%) or multiple allergens (60.6%). Sodium tetrachloropalladate was the most sensitising allergen with 98 patients (27.2%) testing positive, followed by nickel sulphate (23.3%), methylisothiazolinone (15.6%), and fragrance mix I (14.2%). Clinical relevance was found in 68 of 208 patients (32.7%), with patients having one (15.4%) or multiple (17.3%) patch test reactions clinically relevant to their (peri)oral complaints. Conclusions: Clinically relevant patch test reactions were frequently seen in dental patients. Although this study provides us with a better understanding on the frequency and clinical relevance of contact allergy in dental patients, further studies are needed to confirm our results.