Spring may be long gone, but the sneezy, weepy, red-eyed season is still running strong for some folks. Being allergic to grass and pollen is bad enough, but what about the poor individuals who are burdened with a cannabis allergy? It might be surprising to some readers, but a small portion of the population cannot consume cannabis without having uncomfortable allergic reactions to the plant. Luckily, cannabinoid extractions make it possible for many to still gain the benefits of medical marijuana without the discomfort of a bad response.

The good news is that it seems like the number of people who are negatively affected by cannabis allergies is very small. But now that pot is legal in New Mexico, new users will be attracted to the drug, and that number will likely rise.

What are Allergies?

We are all familiar with allergies. They’re those things that make people sneeze when the flowers are blooming or swell up when they get a bee sting.

The mechanism behind allergies is very strange though. It’s triggered when a foreign substance enters the body and causes a negative reaction. That foreign object is known as an allergen. Allergens are actually harmless to most people and include pollen, dust, insects, foods and other sources. For some bodies, though, these allergens set off alarm bells in the immune system, triggering the release of histamines—chemicals that cause you to react in a way that is meant to expel the intruder. It’s no coincidence that these chemicals make people sneeze, cough and cry.

The problem is that the intruder isn’t actually doing any harm—at least compared to what the histamine is doing.

What’s interesting about this topic is that there is evidence that cannabis can help curb the production of histamines, meaning it could potentially help fight allergic reactions (as long as those reactions are in response to something other than the cannabis itself).

Allergic Reactions to Weed

According to a 2015 paper published in Annals of Allergy, Asthma and Immunology, “cannabis pollen inhalation has been noted to cause symptoms of allergic rhinitis, conjunctivitis and asthma.”

But separating the symptoms of an allergic reaction to cannabis from the normal side effects of smoking the drug can often be troublesome. Allergic reactions like coughing, red eyes, itchy throat and nasal congestion are unfortunately very similar to side effects experienced by most cannabis users when they smoke or vape the drug. Most users don’t have to worry at all when they experience these symptoms. It’s only a problem if they notice that the symptoms get worse every time they use pot. Allergic reactions (including those associated with cannabis) may not be triggered the first few times someone comes into contact with an allergen.

Those who are allergic to marijuana can also experience nausea, itchy eyes, runny nose or sneezing after eating, smoking or vaping it. Touching the plant matter might also result in skin reactions like itchiness, dry or inflamed skin and hives. These are not normal reactions to the drug and can be taken as a strong indication that an allergy is present.

Very rarely, using cannabis can actually cause some people to suffer from a severe allergic reaction known as anaphylaxis—a dangerous condition that could leave users struggling to breathe and can even lead to coma or death. Anaphylactic reactions occur with all allergens—not just weed—in the folks who are prone to it. Anaphylactic attacks can be treated with an adrenaline shot if it’s administered quick enough.

In very rare cases, users might be troubled by cross-reactivity with other allergens. This happens when proteins from the cannabis plant resemble those of an allergen and trigger the same response in a victim as though the actual protein had been present. This is reportedly found among those who are allergic to certain foods like almonds, chestnuts, hazelnuts, apples, bananas, eggplant, grapefruit, peaches and tomatoes. Some people who suffer from hay fever may have problems with cannabis because of cross-reactivity.


Many doctors are able to test for cannabis sensitivity the same way they do for other allergies. If you’re concerned that you might have an allergy, you can ask your doctor if they offer skin prick or blood tests that detect pot allergies.

The skin prick test involves penetrating the top layer of skin with a needle bearing different allergens. The skin is observed for allergic reactions. The needle only barely enters the skin, so this kind of test is fairly easy and not very painful.

Simple blood tests can also be used to detect allergies and might be even more accurate than the prick test. For these, a doctor will collect a sample of blood and examine it, looking for antibodies to an allergen. If those antibodies are present at higher numbers than normal, it indicates that the patient likely has an allergy.

Treatment of a cannabis allergy is the same as that of other allergies. The only way to truly mitigate the reaction is to cut off contact with the plant. But antihistamines, intranasal corticosteroid sprays and ophthalmic antihistamine drops can be used to relieve symptoms.

Symptoms But No Allergy

And for those patients who suffer allergic reactions while consuming cannabis but have tested negative for cannabinoid allergies, they are likely having an allergic reaction to some other compound present in the flower they are purchasing that isn’t the plant itself. And the answer may be to switch to concentrates.

Local medical cannabis extraction expert and consultant Alejandro Garcia says he suffers from allergic reactions when he smokes flower. “One of the reasons that I switched to concentrates was to avoid the pollen and environmental contaminants that are normally found in the plant,” he says. “And as much as producers try to mitigate mold, powdery mildew and other microscopic substances, there’s always the chance that there might be some in whole flower. During extraction, these contaminants are trapped in the filters, making concentrates a cleaner product that only contains cannabinoids. As long as you’re not allergic to the cannabinoids, you should be able to bypass that allergic reaction.”