D2.79 - Cannabis Sensitization as an Underrecognized Airborne Trigger in Uncontrolled Asthma: A Case Report

Cannabis is considered a rare aeroallergen and is therefore often overlooked in the diagnostic evaluation of asthma. However, cannabis exposure is increasingly relevant in clinical allergy practice and may act as an airborne trigger in patients with allergic airway disease. We report a case of uncontrolled asthma and seasonal allergic rhinoconjunctivitis (SAR) associated with cannabis sensitization after a symptom-free interval, triggered by recurrent passive exposure.

Within the “#BerlinBreathing” study, patients with SAR were evaluated by structured clinical history, skin prick testing (SPT), multiplex and singleplex specific IgE testing. Among them was a 61-year-old woman with SAR and asthma since adolescence. Childhood history was notable for recurrent rhinitis and respiratory infections. She recalled her first acute asthma episode at age 13 after chlorine gas exposure during competitive swimming. Between ages 17–25, she reported regular cannabis smoking. At 19, ingestion of cannabis-containing cookies led to circulatory collapse with dyspnea, suggestive of a possible anaphylactic reaction. Despite a 30-year symptom-free interval without cannabis use, asthma and SAR symptoms recurred in her late 50s. She currently reports difficult-to-control asthma with exertional dyspnea and frequent reliever use (>2x/week). Notably, passive exposure to her neighbor’s cannabis smoke worsens wheeze and dyspnea.

SPT was negative for all common inhalant allergens. Component-resolved diagnostics showed IgE to Fag s 1 (3.19 kUA/L) from silver beech, Cor a 1.0401 (0.34 kUA/L) from hazel pollen, but no IgE to birch pollen allergens. Further, IgE to the non-specific lipid transfer protein (nsLTP) Can s 3 (2.22 kUA/L) from Cannabis sativa led a broader IgE response to plant food-related nsLTP. An additional singleplex test with cannabis PR-10 protein Can s 5 was negative. The patient reported oral allergy symptoms to apple and hazelnut and aversion to several plant foods.

This case highlights the relevance of cannabis sensitization in a patient with uncontrolled asthma and pollen-food-syndrome. Recurrent passive cannabis smoke exposure was clinically associated with asthma worsening, even after a long symptom-free interval and abstinence from active cannabis use. Rare aeroallergens such as cannabis should be considered as potential, underrecognized triggers in patients with difficult-to-control asthma.

Written informed consent for publication was obtained from the patient.