Tin Sensitization in Belgium and the Netherlands: Complementary Findings From Two Independent Retrospective Studies.

BACKGROUND: Tin is a known but traditionally considered infrequent contact allergen. In recent years, several case reports have reported clinically relevant reactions to tin-containing oral hygiene products, particularly toothpastes. OBJECTIVES: To assess the prevalence and clinical relevance of tin sensitization in consecutive patch-tested patients, as well as in a selected cohort of patients referred because of suspected metal allergy or (peri)oral complaints. MATERIALS/METHODS: Two independent retrospective cohorts were analyzed: 1919 consecutive patch-tested patients from the University Hospital Antwerp, tested with different tin preparations and 536 selected patients from Amsterdam UMC, referred because of suspected metal allergy or (peri)oral complaints and patch tested with tin chloride. RESULTS: In the consecutive cohort, 128/1919 patients (6.7%) tested positive to at least one tin preparation, of whom 35 (27.3%) had clinically relevant sensitization. In the selected cohort, 61/536 patients (11.4%) were sensitized to tin, with 16/50 assessed patients (32.0%) considered clinically relevant. Amongst clinically relevant cases, (peri)oral involvement was the most common presentation in both cohorts, followed by periorbital dermatitis in the consecutive cohort. CONCLUSIONS: Tin sensitization appears to be more common than previously recognized. Although (peri)oral involvement was the predominant clinical presentation, periorbital dermatitis was also frequently observed amongst patients with clinically relevant sensitization.