As the weather warms in Washington, local pollen counts rise and take to the skies causing many to experience the usual itchy eyes, runny nose, coughing, and sneezing typically associated with seasonal allergies. According to the American College of Asthma, Allergy, and Immunology, more than 50 million Americans experience allergies annually, whether it be to a certain food, pollen, mold or pets.

However, there is one plant that can cause allergies that tends to be scrutinized with more than the average concern. Cases of cannabis allergies have been emerging at a growing rate since legalization, and can frequently affect budtenders, recreational consumers and medical patients with a variety of symptoms. As legal cannabis progresses across the U.S., cannabis allergies have been attracting increased attention from researchers.

Marijuana as an allergen

There are several attributes specific to cannabis and its production that make it particularly interesting as a source of allergies. First, as with ragweed (one of pollen’s worst offenders), cannabis pollen grains are buoyant, allowing for distribution across great distances, which increases effectiveness as an irritant. Additionally, pollen, typically produced by male plants, can also be produced by females that express hermaphroditic male flowers. Finally, the isolation of female flowering plants increases the plant’s psychoactive properties by raising its THC content. As a result, the potency of cannabis has increased significantly over the years; on the flip side, THC has been identified as a potential cannabis allergen.

Allergies are basically an immune overreaction by the body as it attempts to protect the respiratory system from outside invaders. The antibodies produced by the body succeed in keeping the perceived foreign invaders out, but also cause the symptoms characteristic of allergic responses.

An article recently published by researchers in Belgium entitled, “Emerging allergens: Cannabis,” specifically focused on cannabis sativa, and found that the plant can cause several allergic symptoms, including (but not limited to) allergic rhinitis (hay fever), conjunctivitis (pink eye), skin rashes, and asthmatic symptoms when smoked, inhaled, or chewed.

Since there are a multitude of ways in which cannabis can be consumed (smoked, vaporized, chewed, taken as a tincture, or a topical) allergic reactions can present in multiple ways. However, a true allergy is a reaction to a specific substance contained within the cannabis plant.

Pollen or smoke exposure has resulted in nasal congestion, rhinitis, sneezing, conjunctival injection, pharyngeal pruritus (itchy throat), coughing, wheezing, and dyspnea (difficulty breathing). Skin contact through handling of plants has been associated with urticarial (hives), generalized pruritus (itching), and periorbital angioedema (swelling). Anaphylaxis, a serious reaction, associated with ocular symptoms, urticaria (hives), angioedema (swelling), dyspnea (difficult breathing), and dysphonia (difficulty in speaking) has been reported as a result of hemp seed ingestion. Finally, allergic asthma triggered by seasonal and occupational exposure to cannabis also has been reported.

The good news is that cannabis allergies can be treated in much the same way as other allergies. The bad news is that due to a lack of standardization in testing limits, much research is still needed to more accurately define the allergens. Until more research is done, it remains difficult to establish diagnostic specificity and clarify treatment options.

How is a cannabis allergy diagnosis made?

Much like other airborne substances that can trigger allergic reactions, cannabis sensitization can be influenced by aerobiology. People who live in areas where large quantities of marijuana plants are grown may be more susceptible to allergic reactions.

Cannabis pollen has been shown to cause allergic reactions in several studies, and individuals who show sensitivity to it are usually also sensitive to pollen from other plants. Seventy three percent of patients report respiratory symptoms during the cannabis pollination season. Sensitization associated with cannabis consumption also has been suggested. Studies have demonstrated a higher prevalence of skin test reaction positivity in marijuana smokers (14.6%) and even more so in those who reported frequent consumption (18.2%) compared with nonsmokers (5%).

The evaluation of cannabis allergies is dependent largely on skin testing. An allergist will perform a skin prick test to detect if a person is sensitive to a specific allergen. If sensitive, to protect the body from a perceived threat, the immune system produces a type of antibody resulting in a reaction from the prick. Additional blood tests can determine if a person is allergic to a substance.

Who is at risk?

The risk of reaction is higher for those who directly inhale cannabis by smoking or vaping. Secondhand cannabis smoke may also cause a reaction in particularly sensitive populations and contact with the plant can often trigger allergic skin reactions. Workers in the industry are particularly susceptible.

Some foods that have similar allergen properties to cannabis may cause an allergy cross-reaction. Reactions to almonds, apples, eggplant, grapefruit, peaches, tomatoes or chestnuts are often indictive of a potential reaction to cannabis.

A recent small-scale study from 2018 reports that people are more likely to have a cannabis allergy if they have allergies to cat dander, molds, dust mites, or plants, but there is no definitive research.

Is treatment available for cannabis allergies?

Frequent marijuana smokers, with symptoms of nasal congestion and chronic cough, can find great relief from an allergy nasal spray and/or inhaler. Asthma symptoms that may be exacerbated by marijuana exposure can improve significantly with a prescribed medication program. EpiPens are prescribed for patients with a history of anaphylaxis, and treatment is readily available for allergy sufferers depending on the seriousness of the reaction. Ultimately, for the chronically allergic cannabis consumer, avoidance is recommended.

If smoking cannabis causes allergy-type symptoms, you may want to switch to edibles. If handling the plant causes a skin reaction or other symptoms, covering exposed parts of the body by wearing gloves and a face mask will prevent inhaling any mildew or mold. Using an over-the-counter allergy medication may also help ease symptoms, and an inhaler could help breathing issues.

Legal limitations to obtain cannabis continues to pose a challenge to learn more about cannabis through further research. As more instances of cannabis allergies are reported and treated, the medical community will be better educated to recommend treatment and guidance. Until then, use common sense, get treatment if needed, and engage the same respect you would for any naturally occurring multicellular organism.

Kate A. Miner has a degree in visual anthropology, and has worked in marketing and advertising for many years. She writes, takes photos and teaches yoga.