A guide to cannabis allergies and symptoms

Marijuana allergies science reviewed

Think you might have marijuana allergies? According to the American College of Asthma, Allergy, and Immunology, more than 50 million Americans suffer from allergies each year. Cumulatively, that’s a huge number of people who will experience some sort of allergic reaction at a point in their life, whether triggered by a food, pollen, mold, or perhaps a more specific irritant such as cats.

What if, however, you found yourself with an allergic reaction to your job, or to something you greatly enjoyed, or, even worse, to something that you need? Stories of marijuana allergies have grown since legalization. Allergies can hit budtenders, recreational consumers, and medical patients with a variety of symptoms.

For example, a typical email we receive goes like this:

Let’s investigate the matter further.

An unusual background: marijuana allergy research

After scooting beneath the radar of the scientific community for the longest time, marijuana allergies appear to be on the rise. Just as cannabis consumption has gone mainstream in the U.S., cannabis allergies have attracted increased attention from researchers. The correlation between the rise in allergies and the increase in legalization initiatives looks significant.

From the outset, we should outline a number of quixotic attributes specific to cannabis and its production that make it particularly interesting as a source of allergies. First off, similar to plants such as ragweed, cannabis pollen grains are very buoyant. They can travel many miles, which can increase their effectiveness as an irritant. Though typically only produced by male plants, females can also make pollen when they express hermaphroditic male flowers. That there are a variety of preparations of cannabis sativa adds another level of complexity.

As you may know, there are a multitude of ways to take cannabis products. You can smoke it, vape it, eat it, take it as a tincture, or uses it as a topical lotion. In addition to these factors, the isolation of female flowering plants, which aims to prevent pollination, increases the plant’s psychoactive properties by raising its THC content. As a result, the potency of cannabis has increased drastically over the years. Tragically, this could also play a role in allergic disease because research suggests THC as a potential cannabis allergen.

Can you really be allergic to cannabis?

Allergies are an immune overreaction by the body attempting 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. Pollen cpmprises the most common allergen. Mold spores grow on rotting logs, dead leaves, and grasses. While dry-weather mold species exist, many types of mold thrive in moist conditions.

Perhaps not so shockingly, given that both these allergens are associated with cannabis, researchers in Belgium recently published an article entitled “Emerging allergens: Cannabis.” The researchers focused in particular on cannabis sativa, one of the two species we all know colloquially as marijuana. They found that the plant can cause a number of allergic symptoms such as allergic rhinitis (hay fever), conjunctivitis (pink eye), skin rashes, and asthmatic symptoms when smoked, inhaled, or chewed. Yikes!

What are cannabis allergies and their symptoms?

Before getting too far ahead of ourselves, it’s important to differentiate between legitimate cannabis allergy symptoms and allergic reactions to substances found in cannabis that are actually not inherent to the plant, such as molds. Put simply, cannabis can become moldy when stored and people with mold allergies may have reactions. Some people could even experience reactions to both the plant and mold.

Cannabis allergies vs impurity allergies

It’s a tad confusing, but we do have proof. Some studies have shown the presence of fungal contamination in marijuana samples. A case of allergic bronchopulmonary aspergillosis attributed to the fungal contamination of a patient’s marijuana supply has even been described. Doesn’t sound good, right? It took a course of steroids to remedy the situation.

Let’s get precise: a true cannabis allergy involves a reaction to a specific substance contained within the cannabis plant. In “Cannabis Sativa: the unconventional ‘weed’ allergen”, Ocampo and Rans provide an excellent review of the existing literature on the subject. They outline how reports in the medical literature have described episodes of allergic reactions, hypersensitivity, and even anaphylaxis to cannabis in its various forms.

Researchers note cannabis pollen inhalation has can cause symptoms of allergic rhinitis, conjunctivitis, and asthma. Pollen or smoke exposure has resulted in nasal congestion, rhinitis, sneezing, conjunctival injection, pharyngeal pruritus (itchy throat), coughing, wheezing, and dyspnea (difficulty breathing).

Researchers describe cases of skin irritations associated with cannabis consumption. Skin contact through the handling of plants has may cause urticarial (hives), generalized pruritus (itching), and periorbital angioedema (swelling). Reports exist of anaphylaxis (a serious reaction) associated with ocular symptoms, urticaria (hives), angioedema (swelling), dyspnea (difficult breathing), and dysphonia (difficulty in speaking) as a result of hemp seed ingestion. We’ve also seen reports of allergic asthma triggered by seasonal and occupational exposure to cannabis.

Researchers have also studied cannabis consumption as a contributing factor in a case of eosinophilic pneumonia.

Varying means of exposure to cannabis allergens

Much like other airborne substances that can trigger allergic reactions (pollen, we’re looking at you!), the local air may influence cannabis sensitization. People who live in areas where large quantities of marijuana plants are grown may grown experience more allergic reactions to the pollen.

In Omaha, Nebraska, where the plant reportedly grows wildly and commercially, one study looked at cannabis sensitization. This study noted that 61% of 127 patients with allergic rhino conjunctivitis and/or asthma symptoms had a positive cannabis pollen skin prick test reaction.

Rhino conjunctivitis consists of one or several of the following symptoms:

• Nasal congestion
• Runny nose
• post-nasal drip
• Sneezing
• Red eyes
• Itching of the nose or eyes

Seventy three percent of randomly selected patients in a cannabis-sensitive subgroup reported respiratory symptoms during the cannabis pollination season. Sensitization associated with cannabis consumption also has been suggested. Ominously, this study 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%).

Allergies in the weed workplace

For all the aspiring budtenders out there, allergic reactions associated with occupational exposure to cannabis sativa have been shown. A medical marijuana grower, who previously tolerated personal recreational marijuana consumption, developed skin irritations from handling plants. Two patients who did not consume cannabis noted nasal and respiratory symptoms after several years of work in a laboratory. One patient had more pronounced symptoms with handling of the sinsemilla (high-THC marijuana from the female plant), suggesting the possible allergenic role of THC in this case.

Not only that, but some European studies have investigated potential cross-reactivity between cannabis and other plants. Gamboa et al reported on a case of a 28-year-old cannabis smoker with progressive allergic symptoms who went on to develop urticaria to peach peel, food pollen syndrome to several foods, and anaphylaxis to tomato, pepper, and fig. Ebo et al further suggested allergic cross-reactivity to fruits, vegetables, and nuts, and even the possibility of a “cannabis–plant food syndrome.”

Identifying marijuana allergens

As we have seen so far, 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. However, this does not explain the cases of cannabis allergy caused by female plants with no signs of hermaphroditism. In these instances, some other culprit must exist.

There have been efforts to identify specific allergens for cannabis with scientists pinpointing a number of possible culprits. A study published in 1971 suggested cannabinoids as allergens based on positive skin prick test reactions in case patients. As we’ve already mentioned, researchers specifically suggested THC in the case of a forensic laboratory worker handling sinsemilla variants of cannabis sativa.

The chemistry of pot allergies

More recently, a study identified a nonspecific LTP (ns-LTP) relevant to cannabis and named it Can s 3. LPTs (Lipid Transfer Proteins) are responsible for the transfer of lipids and other fatty acids across cell membranes and are often involved in food allergies. Further investigation by both Larramendi and Ebo supported the potential of Can s 3 as a major allergen in cannabis allergy.

Additional studies have found ns-LTPs on immunoblotting, an analytical technique used to detect specific proteins. One study, aiming to define cannabis allergens, identified potential allergens including a protein called RuBisCO and a 23-kDa oxygen-evolving enhancer protein 2. Other less consistently demonstrated allergens included adenosine triphosphate synthase, phosphoglycerate kinase, glyceralderhyde-3-phosphate dehydrogenase, and luminal binding protein.

So that’s the science. The diagnosis process is pretty simple though.

How are marijuana allergies diagnosed?

If you think you might have a cannabis allergy, what’s your next step? What do you do? Where do you go? Well, it’s pretty simple. You book an appointment with an allergist, of course.

How to test for herb allergies

The evaluation of cannabis allergies largely focuses on skin testing. A skin prick test can detect if a person has allergies to a specific allergen. The tests are not invasive and tend to produce quick results.

A positive skin prick test to a particular allergen does not necessarily indicate that a person will experience a reaction caused by that allergen. Therefore, healthcare practitioners must compare the skin test results with the time and place of a person’s symptoms to see if they match. If the results of prick tests are negative, intradermal tests may follow, which give allergists more details about what’s causing the underlying symptoms. After either test, doctors watch the area of the skin for about 15 minutes to see if a reaction develops. The “wheal” (an itchy, red bump) and “flare” (surrounding redness) indicate the presence of an allergy antibody. The larger the wheal and flare, the greater the sensitivity to the allergen.

Although skin testing may seem simple, only trained practitioners should perform it. Extracts for testing are typically created with crushed buds, leaves, and flowers of the cannabis plant.

Is treatment available for marijuana allergies?

William Silvers, a Colorado allergist, published an editorial in February 2016 discussing three recent patients with symptoms suggestive of marijuana allergies.

One patient, a frequent marijuana smoker, experienced nasal congestion that later developed into a chronic cough once he began work as a trimmer at a marijuana growth facility. Treatment with a nasal spray and inhaler helped to reduce symptoms.

A second patient, without any prior history of asthma or allergies, got allergies when he began work in a grow facility and dispensary. Doctors diagnosed him as having asthma exacerbated by marijuana exposure with hay fever, eye inflammation, and suspected contact dermatitis to marijuana. Treatment recommendations included minimizing his environmental exposure to marijuana as much as possible. The patient significantly improved with a prescribed medication program.

The final patient, a heavy marijuana consumer, received a referral by an emergency department physician with suspected anaphylaxis from weed exposure. He admitted to smoking concentrate, a carbon dioxide extracted marijuana wax, that contained up to 60% to 70% THC levels. Puzzlingly, he showed a lack of sensitization to marijuana extracts and pollen tests came back negative. The wax concentrate might have contained a contaminant or additive.

‘A mild allergen’

Despite the low, mumbled presentiments of an epidemic, in Dr. Silvers’ opinion:

This sounds like good news for cannabis lovers and, as demonstrated, allergy sufferers have a treatment. Unfortunately for the chronically-allergic cannabis consumer, as with other allergens, doctors say stay off the grass.

Still, one must consider factors such as local aerobiology and occupational exposures. Patients can use antihistamines, intranasal steroids, and nasal decongestants to treat symptoms of allergic rhino conjunctivitis. You can treat asthma with Beta agonists or an inhaled corticosteroid if required. Doctors can prescribe EpiPens for patients with a history of anaphylaxis.

There have even been rare cases of treatment with immunotherapy in the literature. One report demonstrated desensitization in two patients. Researchers noted improvement in a cohort of hemp workers who received immunotherapy extract twice a week for a year. For those experiencing symptoms, we’re not claiming that a cannabis-allergy Kryptonite has been discovered, but there are certainly a variety of options out there.

Conclusions

Although still relatively uncommon, allergies associated with cannabis are being reported with increased frequency. Allergic reactions as severe as anaphylaxis attributed to cannabis have been noted with sensitization associated with pollinosis, cannabis consumption, occupational exposure, and potential plant cross-reactivity. However, don’t panic. We expect reporting of cannabis allergies to increase as cannabis consumption becomes more mainstream.

Doctors treat cannabis allergies in much the same way as other allergies. However, we need more research to better define allergens, develop a standardized extract, establish diagnostic specificity, and clarify treatment options for patients.

Without a shadow of a doubt, the legal limitations to obtaining cannabis extracts poses challenges. The only federally approved source of cannabis species in the United States comes from the University of Mississippi. Prohibition creates obstacles for patient reporting. If we’re to learn more about cannabis allergies, we need to overcome the former by enabling more wide-ranging research. We need to encourage silent cannabis allergy sufferers to speak up.