Rate of actual metal allergy prior to dental treatment in subjects complaining of possible metal allergy.

BACKGROUND: Dental treatment for patients with self-reported metal allergy or concern about the possibility of having such an allergy is often difficult; such patients often undergo dermatological consultations for metal patch test (PT). OBJECTIVE: This study compared PT results for metal allergens and the clinical relevance of this among patients visiting Fukuoka Dental College Hospital. METHODS: We performed PT with metal allergens on patients with oral mucosa- or skin-related symptoms, or those concerned about adverse events associated with upcoming dental treatment. RESULTS: Fifty-nine patients were patch-tested with metal allergens. Thirty-four cases (58.8%) had self-reported metal allergy. Regarding comorbidities, atopic dermatitis was the most common (7 cases), followed by hand eczema, palmoplantar pustulosis, lichen planus, and abnormal sensation in the mouth. Overall, 25 of 59 cases had at least one positive PT reaction. The most common positive allergen was nickel sulfate (17 cases), followed by cobalt chloride, zinc chloride, and palladium chloride. The rate of positivity of metal PT was significantly higher in the self-reported metal allergy cases than in the others (P < 0.001). Other comorbidities were not significantly associated with those with or without self-reported metal allergy. Five of those without self-reported metal allergy showed positive PT reaction. CONCLUSIONS: Patients with self-reported metal allergy exhibited more metal PT reactions than those without this. One fifth of those without this showed positive metal PT reaction, implying the importance of PT for both with and without self-reported metal allergy. PT results are helpful for selecting dental metals for future prosthetic and orthodontic treatments.