A new-old allergen: propolis contact hypersensitivity 1992-2021

Introduction: Propolis is a resinous substance collected by bees. Its use is widespread in cosmetics and natural medi-cine because of variable beneficial effects. Local application and consumption may cause hypersensitivity.Objective: Aim of this study was to analyze the 30-year data of patients with propolis hypersensitivity.Method: 17 784 patients were patch tested between 1992 and 2021 in the Allergology Outpatient Unit of the De-partment of Dermatology, Venereology and Dermatooncology of the Semmelweis University. 464 patients (2.6%) had propolis sensibility. We present the annual changes in the frequency of propolis sensibility, the typical diagnoses, age groups, localizations most affected by clinical symptoms and the co-hypersensitivities according to propolis sen-sibility.Results: In the 30-year period, the sensitization frequency of propolis was on average 2.6%; in 2019-2021, we de-tected a sudden increase (6.2%, 8.4%, 6.9%). Female predominance was typical (70.7%). Most patients belonged to the age group 51-60 years (24.6%), the mean age was 52.5 years. Most skin symptoms appeared on hands (34.2%), legs (18.4%), and face (17.5%). Regarding co-hypersensitivities, fragrance mix I (27.7%), balsam of Peru (26.8%) and wood tar (23.0%) can be mentioned.Conclusion: The general need for biocosmetics, complementary and alternative medicine raises the exposure of propolis. The risk of contact hypersensitivity is increased because propolis products are used mostly on inflamed skin with higher allergen penetration. According to our results, propolis - beside its advantageous properties - is an important environ-mental allergen, especially among elderly women. Propolis sensibility, the possible cross-and co-hypersensitivities can cause contact dermatitis or may worsen different skin diseases. Propolis sensibility can be verified by patch testing.