The importance of propolis in patch testing--a multicentre survey.

Background: Propolis is widely used in 'natural' cosmetics, remedies, and over-the-counter products. The incidence of propolis allergy is increasing, and cross-reaction with fragrance mix I (FMII), colophonium, and Myroxylon pereirae can occur.

Objectives: To find out the prevalence and clinical relevance of positive patch tests to propolis and assess cross-reactions with Myroxylon pereirae, colophonium, FMI, and beeswax.