Abstract
The chemical composition of propolis varies with geographical origin; however, it is not known whether this affects the frequency of contact allergy to propolis. In order to study the frequency of contact allergy to propolis of different geographical origins and concomitant reactions, 1,470 consecutive patients with dermatitis from Denmark, Lithuania and Spain were patch tested with propolis from China, Lithuania, North America and Sweden, and with a baseline series. Patch test reactions to any type of propolis ranged from 1.3% to 5.8%. There were no statistically significant differences in the frequency of positive reactions between the 4 types of propolis in the respective countries. Testing with a single commercially available type of propolis detects only approximately half of propolis-allergic patients. In patients allergic to propolis, concomitant reactions to Myroxylon pereirae resin, colophonium and Fragrance mix I were common, ranging from 12.5% to 50.0%.