Occupational Allergies to Cannabis

Abstract

Within the last decade there has been a significant expansion in access to cannabis for medicinal and adult nonmedical use in the United States and abroad. This has resulted in a rapidly growing and diverse workforce that is involved with the growth, cultivation, handling, and dispensing of the cannabis plant and its products. The objective of this review was to educate physicians on the complexities associated with the health effects of cannabis exposure, the nature of these exposures, and the future practical challenges of managing these in the context of allergic disease. We will detail the biological hazards related to typical modern cannabis industry operations that may potentially drive allergic sensitization in workers. We will highlight the limitations that have hindered the development of objective diagnostic measures that are essential in separating "true" cannabis allergies from nonspecific reactions/irritations that "mimic" allergy-like symptoms. Finally, we will discuss recent advances in the basic and translational scientific research that will aid the development of diagnostic tools and therapeutic standards to serve optimal management of cannabis allergies across the occupational spectrum.

Keywords: Allergy; Cannabis; Occupational.

Figure 1.. Primary and secondary health hazards associated with occupational exposures to cannabis.

An investigation into a simplified flow of the occupational tasks that occur within the cannabis industry indicates numerous opportunities for direct (and possibly prolonged) exposures to cannabis that may affect worker health and drive allergic sensitization. The green sphere describes the cycle of cannabis cultivation, processing and distribution, and emphasizes the risk of direct exposures to the plant. Workers involved in cultivation, destemming and trimming operations may have elevated risks for disease owing to prolonged direct contact with the plant. Exposure to cannabis related biological hazards is not limited to just the grow facility, and could extend to transportation workers, budtenders or retailers. The yellow sphere identifies potential secondary risk factors that may drive sensitization alone (mold) or act as adjuvants (endotoxin, pesticides, THC) and promote cannabis sensitization. Further, underlying host factors such as atopy and asthma may also represent risks for exacerbation and diseases. Indoor work environments may also increase sensitization risk if poorly ventilated. Cannabis grow cycle details obtained from www.leafly.com.

Figure 2.. Flow chart showing proposed diagnostics steps in establishing occupational cannabis allergies.

This scheme is based on evidence from examining allergic sensitization to cannabis among non-medicinal users. In absence of strong evidence from occupational allergy cases, this diagnostic algorithm should be considered as a proposal with an expectation that this approach will be refined as more data is available in the future. As indicated literature indicates that testing should be done only in symptomatic individuals. Any symptomatic exposure to cannabis in the workplace will need thorough evaluation of the exposure history. While asymptomatic workers are unlikely to seek medical attention, this group may be included in any employment pre-screening, surveillance and monitoring programs. Skin prick testing with crude protein extracts generated from cannabis or from dust samples from specific operations may be helpful in establishing specific allergic sensitization. Further, additional laboratory-based investigations using ImmunoCAP, BAT, CBA (with specific allergens Can s 3 and Can s 4) and immunoproteomics will assist in allergen identification and validation. In workers with a negative SPT to crude allergens, further testing is not essential. For negative SPT to specific allergens, cannabis allergies could be still possible, although it rules out Can s 3 and Can s 4 as potential allergens.