An occupational respiratory allergy caused by Sinapis alba pollen in olive farmers

Sinapis alba (white mustard) is a entomophilic species included in the Brassicaceae family. To date it has not been related to allergic sensitization or clinical respiratory disease.

Twelve olive orchard workers had a history of rhinitis and/or bronchial asthma that occurred during control weed management and/or harvest, from January to March. They underwent skin prick tests (SPT) with S. alba pollen extract and a standard battery of aeroallergens. Sinapis alba pollen extract was prepared for performing quantitative skin tests, enzyme allergosorbent test and nasal challenge test (NCT). A portable monitoring station and an urban volumetric Hirst-type spore trap were used for the aerobiological study.

Eleven patients suffered from rhinitis and bronchial asthma and one had only from rhinitis. All patients were sensitized to S. alba pollen extract, and they showed a positive NCT response. In the urban aerobiologic monitoring station the amount of S. alba pollen only exceptionally reached peaks of 21 grains/m(3), whereas in the work environment peaks of 1801 grains/m(3) were detected between 15 February and 7 April.

We demonstrate the existence of a new occupational allergen for olive farmers: S. alba pollen. We point out the importance of perform aerobiological sampling within the occupational environment for the detection and quantification of the allergenic source.