Although there’s never been a death directly linked to cannabis use, at least according to the Centers for Disease Control and Prevention (CDC), it is possible for people to have allergic reactions to the plant just as they can with other plants and pollen. Symptoms can range from mild to severe and, depending on the severity, may require immediate medical attention. From cannabis allergy causes and the symptoms to look out for, here’s what you need to know about allergies and cannabis.  

The cause 

As with many other types of plant allergies, most individuals who are allergic to cannabis are actually allergic to its pollen. As a result, one doesn’t necessarily have to smoke or eat the cannabis themselves to have a reaction -- even just being exposed to secondhand smoke or touching the plant with their hands can trigger an allergy. A 2018 study reports that individuals who are allergic to cat dander, mold, dust mites, and other plants are more likely to have a cannabis allergy. 

It’s important to note that the 2018 study was very small and that more research is needed before any type of link can be solidified. 

Colton Boettinger, CULTA’s operations supervisor in the CULTA dispensary, has a cannabis allergy and believes the source of his own allergy is the conditions the strain was grown in. For him, outdoor strains seem to trigger his allergy symptoms more than indoor strains, and he’s particularly sensitive to cannabis with a lower moisture content. Of course, as he points out, there isn’t hard science to back this up. If you think you have an allergy, it’s important to monitor your symptoms and be in tune with your body. 

Note: Preliminary research has also pointed to other parts of the plant (including the terpenes linalool and limonene) as potential allergy triggers but, again, more research is needed in this area. Generally speaking, pollen seems to be the most likely reason for cannabis allergies. 

The symptoms 

The signs or symptoms of a cannabis allergy ultimately depend on how the allergy sufferer was exposed to the plant (ex: orally or through skin contact.) Common symptoms of a cannabis allergy are similar to other allergies, including a dry cough, congestion, itchy eyes, a runny nose, sneezing, and a sore or itchy throat. If contact occurs via the skin, other symptoms like blisters, dry skin, hives, itchiness, or red skin may also accompany the other symptoms listed above. 

For Colton, his symptoms more or less fall in line with the above. “Usually when dealing with larger quantities, more specifically smelling larger quantities, my arms tend to break out in red itchy spots [and my] eyes get watery, and I start having "sneeze attacks",” says Colton. 

Symptoms generally begin immediately after exposure to the plant but, in some cases, can take a couple hours to appear. If you experience any of the above symptoms after being exposed to cannabis, immediately stop smoking or handling the plant to keep your symptoms from getting worse. 

In very rare and very severe cases, cannabis can cause a severe allergic reaction called anaphylaxis. This is a life-threatening condition that occurs within seconds of exposure, and symptoms include: 

• Difficulty breathing
• Dizziness
• Fainting
• Itchy and flushed or pale skin
• Low blood pressure
• Swollen tongue or throat
• Weak and rapid pulse
• Vomiting

Anaphylaxis can result in a coma or death, so get help immediately if you or someone else is experiencing any of the above symptoms after consuming, holding, or inhaling secondhand cannabis smoke. When in doubt, err on the side of caution and get professional medical help immediately. 

Diagnosis and treatment 

Diagnosis can be tricky, as there is no standard way to test for a cannabis allergy. If you suspect you have a cannabis allergy, your doctor may wish to diagnose a cannabis allergy the way they would any other type of allergy: via a blood test or skin prick test. 

• Skin prick test- It may sound painful, but skin prick tests are non-invasive and results come back immediately. During a skin prick test, your doctor will apply diluted cannabis to the surface of your skin with a needle. If a welt, redness, or itchiness occurs within 15 minutes, it’s likely you’re allergic to cannabis. 
• Blood test- If your doctor uses a blood test to diagnose your cannabis allergy, they’ll take a blood sample and check it for cannabis antibodies. If you have a higher level of antibodies in your blood than expected, you’re more likely to be allergic. Blood tests may be more accurate, but the results take longer to come back and are more expensive than skin tests. 

Ultimately, your doctor will be able to determine which test is the best for you after he or she asks you some preliminary questions. Unfortunately, there is no treatment for a cannabis allergy outside of avoiding the allergen altogether. In this case, prevention really is the best medicine. If you have a severe cannabis allergy (such as one that results in anaphylaxis), you should carry an Epipen with you at all times in case of accidental exposure. 

Colton has never been formally diagnosed, but takes an antihistamine before dealing with certain strains to prevent allergy symptoms. If he’s already experiencing symptoms, Benadryl usually does the trick. We asked Colton for some prevention tips and offered this advice: wear disposable latex gloves and a mask when handling cannabis and avoid touching or rubbing your eyes after handling cannabis. 

Cross-reactivity with other allergies 

Cross-reactivity is when someone who is allergic to one thing also experiences allergic reactions to other things that share similar proteins. In the case of cannabis, individuals with cannabis allergies may also be allergic to foods with proteins that resemble cannabis proteins, including: almonds, apples, eggplant, bananas, chestnuts, grapefruit, peaches, and tomatoes. 

A couple different studies have tested this. One from 2013 tested 21 patients with food allergies for reactivity to cannabis -- 12 were also allergic to cannabis and all 12 had more severe reactions to food than cannabis. A 2008 study tested patients for an allergic reaction to cannabis, tomato, peach, and pollen. All subjects with tomato sensitivities also experienced a reaction to cannabis, and cross-reactivity with peach peel and cannabis was also prominent. 

Again, these studies were small and not enough to directly link cannabis with other food allergies, but it’s an interesting look at the concept of cross-reactivity and how it relates to cannabis. 

Are reported cases increasing? 

It might seem like reported cannabis allergy cases are increasing, but this is likely because cannabis is being used more often medicinally and, in states where it’s legalized for adult-use, recreationally. As the medication becomes less taboo, patients become more aware of how their bodies react to the plant. To learn more about cannabis allergies, speak with your certifying provider or another medical professional for more information. 

To learn more about the science behind how cannabis interacts with your body, read our blog on the endocannabinoid system.