Cannabis allergy: what the clinician needs to know in 2019

ABSTRACT

Introduction: Although the use of cannabis dates back millennia, the first description of cannabis allergy is relatively recent (1971). Recent large-scale data show that cannabis allergy can manifest severe and generalized symptoms with extensive cross-reactions. Thus, it is essential to become familiarized with its clinical presentation, diagnostic aids, and adequate therapeutic guidance.

Areas covered: Here we provide a hands-on overview on cannabis allergy focusing on symptomatology and the reliability of diagnostic options. Recent advances in proteomics are discussed in detail, elucidating the link with nsLTP-related allergies. The proteomics advancements have paved the way for more reliable diagnostics, especially component-based tools. Finally, the current experience in treatment options is highlighted.

Expert opinion: Cannabis allergy is an allergy entity which can significantly impact the quality of life. For optimal diagnosis, we advise to start with a validated and standardized crude-extract based test such as sIgE hemp complemented by component-based diagnostics such as sIgE Can s 3 quantifications where available. Future research should lift the veil on the true prevalence of cannabis allergy and the importance of other cannabis allergens to further guide our practice.

KEYWORDS:

• Cannabis
• hemp
• specific IgE
• basophil activation
• allergy
• skin prick test
• Can s 3
• non-specific lipid transfer protein (nsLTP)

Article Highlights

• Cannabis allergy can elicit a variety of symptoms from mild rhinoconjunctivitis to life-threatening anaphylaxis;

• Crude extract-based diagnostics show a very high sensitivity albeit a low specificity;

• Can s 3, the nsLTP of Cannabis sativa, is a major allergen with Can s 3 based diagnostics showing the highest performance;

• Reports suggest that symptoms can occur after smoking, cutaneous contact but also ingestion of spacecake, cannabis tea, oil or hemp seeds;

• A significant number of patients even report symptoms on indirect smoke exposure or cutaneous contact;

• Cannabis allergy has been described following both recreational use and occupational cannabis exposure.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This work was supported by the Agency for Innovation by Science and Technology (grant number 140185). Furthermore, V. Sabato is a senior clinical researcher of the Research Foundation Flanders/Fonds Wetenschappelijk Onderzoek (FWO: 1804518N). D. G. Ebo is a senior clinical researcher of the Research Foundation Flanders/Fonds Wetenschappelijk Onderzoek (FWO: 1800614N). A. L. Van Gasse is a fellow of the Research Foundation Flanders/Fonds Wetenschappelijk Onderzoek (FWO: 1113617N).