Occupational cannabis exposure and allergy risks.

Objectives: Cannabis allergy has mainly been described following recreational use but some cases also point to cannabis sensitisation as a result of occupational exposure. As a consequence, little is known on the prevalence and clinical phenotype of occupational cannabis allergy. Therefore, this study aims to explore the allergy-associated health risks of occupational cannabis exposure in Belgian police force personnel.

Methods: 81 participants, active in the police force, reporting regular occupational cannabis exposure during the past 12 months, were included. History was combined with a standardised questionnaire on allergies and cannabis exposure.Basophil activation tests (BATs) with a crude cannabis extract and rCan s 3 were performed. In addition, specific (s)IgE rCan s 3 as well as sIgE to house dust mite, six pollen and three mould allergens were quantified.

Results: Although 42% of the participants reported respiratory and/or cutaneous symptoms on occupational cannabis exposure, all cannabis diagnostics were entirely negative, except one symptomatic case demonstrating a borderline result. Furthermore, there is no significant difference between the groups with and without symptoms on cannabis exposure in terms of allergenic sensitisations.

Conclusions: The origins of the reported respiratory and cutaneous symptoms during cannabis exposure remain elusive but are probably due to non-immune reactions. It should be noted that the study was volunteer-based possibly reflecting an excessive number of symptomatic individuals. Nevertheless, as only one participant reported using fully protective gear, much improvement is needed for reducing the number of symptoms reported on duty, independent of their origin.