Contact Allergy to Propolis: Update 2013-2025

This article is an update of our previous review of propolis published in Dermatitis in 2013. It provides brief general information on propolis and a full update of the literature published between March 2013 and May 2025 on contact allergy to propolis, including results of testing in consecutive patients, data on testing in groups of selected patients, case reports, and case series. In addition, coreactivity to fragrances, fragrance-markers, and other compounds is presented and assessed, recent analyses of the components of the propolis materials used for patch testing are detailed, the allergens in propolis are briefly discussed, and data on the frequency of propolis used in cosmetics are provided. Special attention is paid to the sudden appearance of Brazilian propolis (Allergeaze) as patch test allergen, which caught us (and many others) by surprise. We try to elucidate the nature of positive patch tests to this material (allergic, false-positive, both?) and find an explanation for the extremely large number of positive reactions seen in various studies. We argue that propolis is used in few cosmetics and that these products are an infrequent cause of sensitization and allergic contact dermatitis. Rather, the majority may represent cross- or pseudo-cross-reactions in patients previously sensitized to fragrances. It is imperative that in the publication of all studies in which contact allergy to propolis was investigated, the source of propolis test material is specified: Chemotechnique (Chinese propolis) or Allergeaze (propolis = Chinese propolis; propolis [B] = Brazilian propolis).