Marijuana is a plant that contains up to 600 different compounds. It is possible for a person to be allergic to cannabis, and it is usually due to one of the many compounds in the cannabis plant – not necessarily a cannabinoid!
People are often exposed to cannabis allergens in the following ways:
- Inhaling cannabis pollen in the air
- Smoking marijuana, or breathing in second-hand cannabis smoke
- Touching marijuana, called “contact dermatitis”
- Eating marijuana
What Compounds or Parts of the Cannabis Plant Cause an Allergic Reaction?
The most common allergic reaction to cannabis comes from the pollen. As with hayfever, where the pollen of plants causes the immune system to attack the foreign material, causing an extreme immune system reaction. Also similar to hayfever, the most common signs of an allergic reaction are:
- Itchy, red and/or watery eyes
- A dry cough
- A runny nose
- An itchy or sore throat
Some people may also get an allergic reaction from handling the plant. This is called “contact dermatitis”, and the symptoms can include:
- Itchy skin
- Red, inflamed and/or puffy skin
- Dry skin
In rare and extreme cases, a severe allergic reaction called anaphylaxis can occur. Symptoms of anaphylaxis can include:
- Difficulty breathing, which can be made worse by a swollen tongue or throat
- Extremely low blood pressure
- A weak, rapid pulse
- Nausea & vomiting
- Itchy, flushed or pale skin
In such instances, emergency medical care is required.
Is it Possible to Be Allergic to Cannabinoids, Terpenes and Flavonoids?
Although most people are more likely to be allergic to the pollen in cannabis, it is on rare occasions also possible to be allergic to a cannabinoid, terpene or flavonoid in the cannabis plant, just as it is possible to be allergic to a particular drug or foodstuff. The symptoms would be similar to the ones associated with pollen.
Is There a Way to Test for an Allergic Reaction to Cannabinoids, Terpenes or Flavonoids?
As raw cannabis flower has many more compounds in it, there are many more variables to consider when trying to determine which constituent of the plant is causing an allergic reaction.
Perhaps the simplest and safest way to check if you have an allergy to the cannabinoids, terpenes or flavonoids themselves is to prick the skin and handle cannabis extract with little plant material in it (e.g. wax, honey or a little Rick Simpson Oil). This is known as the “skin prick test”. If you get any signs of contact dermatitis, then you may be allergic to the cannabinoids, terpenes or flavonoids themselves. You can also see if you get contact dermatitis after handling raw flower or resin, which could also help you determine what part of the cannabis plant you’re allergic to.
Another way to confirm if you have a cannabis allergy is if you have an allergy to any of the following fruits, vegetables or nuts, as they share some similar protein properties (cross-reactivity):
- Eggplants (aubergine)
Is It Possible to Become Allergic to Cannabis After Repeated Exposure?
As cannabis contains pollen, it can become an irritant if constantly exposed to it after a long time. This is not common with occasional exposure, but if you are near an area where there are hundreds of cannabis plants being grown and there’s lots of pollen in the air, it is possible to become allergic to it after long-term exposure. However, this is not common.
How Common is Cannabis Allergy?
It is not very common to be allergic to cannabis, but it’s not unheard of. Hayfever sufferers may be more sensitive to the pollen in cannabis plants, and certain varieties may be more likely to cause an allergic reaction than others. How common cannabis allergies are across the US we do not know, however.
How Serious is a Cannabis Allergy?
In most instances, cannabis allergies are not deadly, and thankfully most people realize from their symptoms that they’re allergic before they ingest it.
Could Cannabinoids Help Treat Allergic Reactions?
As THC and CBD can dampen immune responses and have antiinflammatory effects, it is reasonable to believe that they could be used to treat mild allergic reactions to some extent. THC, CBD and pinene can also open the airways, making such compounds potentially very useful for asthma and chronic obstructive pulmonary disorder (COPD).
However, there is little evidence that cannabinoids work for treating allergic reactions specifically. It is a promising area of research, though, and CBD could be an alternative to the more powerful, first-generation antihistamines like diphenhydramine (Benadryl), carbinoxamine (Clistin) and clemastine (Tavist), which can all cause drowsiness.