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.

Methods: Two thousand eight hundred and twenty-eight subjects in 10 UK centres were patch tested with propolis and beeswax. Generic data were acquired from British Contact Dermatology Society (BCDS) database and further relevant information was requested by survey of participating centres.

Results: The prevalence of propolis allergy was 1.9% (55/2828). Out of these 55 subjects, only 4 (7.2%) were allergic to beeswax, 22 (40%) to Myroxylon pereirae, 15 (27.2%) to colophonium, and 6 (10.9%) to FMI. Additional data for 41 propolis allergic subjects were collected by questionnaire. Hands were the most common sites of involvement, and cosmetics were the most common source of contact. Eight out of 12 subjects reported improvement in eczema following avoidance of propolis.

Conclusions: Propolis is an important allergen of increasing frequency and its inclusion in BCDS baseline series is appropriate. Cross-sensitivity to beeswax is rare.