Cannabis allergy through passive exposure


Published Online: February 1, 2017

Cannabis allergy seems on the rise and appears mainly to result from a sensitization to Can s 3, the non-specific lipid transfer protein present in Cannabis sativa. Allergic sensitization to cannabis mainly occurs through active consumption with exposure by inhalation, cutaneous contact, ingestion, or intravenous use. Most patients present with rhinoconjunctivitis and asthma and/or pruritus, contact urticaria and/or angioedema. The effects of indirect exposure to cannabis on allergic sensitization are unknown.

Decuyper and colleagues reported in The Journal of Allergy and Clinical Immunology: In Practice on two cases in whom cannabis sensitization and allergy with subsequent cross-reactive food allergies seem to result from passive exposure to cannabis. Both cannabis and food allergies were documented by a thorough history, skin prick tests and basophil activation tests.

One adult and one child both presenting with respiratory and cutaneous allergic symptoms on passive cannabis exposure and denying any previous active exposure to the drug are presented. Both patients also showed more generalized and severe allergic symptoms to different fruits. Diagnosis of cannabis allergy rested upon a thorough history supported by positive skin prick tests (SPT) using an ns-LTP rich cannabis extract, positive sIgE measurements to recombinant Can s 3 and clear basophil activation when stimulated with recombinant Can s 3 protein.

In essence, these case descriptions support the presumption that indirect cannabis exposure without any previous active exposure could have caused sensitization and elicitation of allergic symptoms to cannabis together with development of various LTP-related allergies that extend beyond the joint. Larger studies are needed to confirm these preliminary findings.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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