Marijuana Allergy: Common Symptoms and Treatments

Marijuana allergy is real, rare and affects 1 out of every 100 users. Are you one of them?

Look, there are slim chances that you are but have in mind that marijuana allergy does exist.

It’s just the brutal truth:

There are people who can smoke 5 grams a day for decades and not even flinch (and they are the majority) and then there are those unlucky few who develop an allergic reaction to cannabis and they end up giving up smoking altogether.

I mean, how many Kleenex can you buy before you say it’s enough?

That being said, any contact with the plant can trigger an allergic reaction:

Every time an allergic person consumes marijuana in any way, shape or form he is subjected to a different variety of symptoms, all of which can range from mild to potentially serious if left untreated.

But it’s good to know that you’re not the first person having concerns about this (duh)…

Here’s how marijuana triggers allergic reactions

Marijuana allergy was researched in several clinical studies, but most recently it was mentioned in two publications.

The first one, published in 2013, set about to identify Cannabis Sativa allergens by testing a group of people through skin prick testing.

In their research, they found 17 cannabis users who tested positive for an allergic reaction to cannabis. All patients showed similar symptoms (which you can find below) but, most importantly, this study identified what exactly causes people to be allergic to weed.

The big answer:

Peptides from enzymes connected to the plant’s primary metabolism.

For all of you chemistry geeks out there, these are RuBisCO, oxygen evolving-enhancer protein, ATP synthase, phosphoglycerate kinase, and glyceraldehyde-3-phosphate dehydrogenase.

The second publication came in 2015 — this one categorized cannabis allergy as something similar to fruit and vegetable allergy, therefore placing it in the “cannabis-fruit/vegetable syndrome”.

Some would say that this is minor and that pineapple has never killed anyone. But there’s a twist…

This 2015 study explored various possibilities of cross-allergic reactions with tobacco, natural latex and plant derived alcoholic beverages. Which is pretty good to know, having in mind that weed is often smoked with tobacco, which can be seen in blunts.

If we get rid of this scientific jargon, we can see that these two studies helped us understand something very important:

Marijuana allergy is very rare but when it does occur it has similar symptoms as some common food and plant allergies.

We got the plant’s role down, now we need to address another allergen that can be found in low quality buds:


Mold can be commonly seen on weed that hasn’t been stored and cured properly.

If you remember our weed expiration date article, moldy weed can be toxic and unsmokable, and can even cause respiratory issues in some cases.

Besides being weed’s number one enemy, mold is also an enemy of the humans (it’s basically Batman vs Joker at this point).

When you smoke moldy weed you also inhale mold spores, which can cause symptoms such as itching, runny nose, nasal congestion and similar.

Long term smokers can develop an intolerance also

Marijuana allergy is not limited to first time users. It can happen with long term users as well.

Just so you know.

There is a thing called Cannabinoid Hyperemesis Syndrome (CHS) — if you’re smoking marijuana for a long time you’ve probably heard about it.

According to this 2011 publication by Temple University Hospital, CHS is characterized by chronic cannabis use, cyclic episodes of nausea, vomiting and bathing with hot water (which is a learned reaction apparently).

It develops all of a sudden and ONLY in long-term regular smokers. And it sucks.

I came across this horrific NY Mag interview of a woman that found out she has CHS. She had terrible nausea and vomiting sessions and finally, after a dozen tests, her doctor told her that she developed an intolerance to cannabis.

In the end, she had to quit smoking. Yikes.

The most common marijuana allergy symptoms

All cannabis allergy symptoms usually occur 20-30 minutes after getting in touch with the plant.

And by that I mean any kind of consummation — it doesn’t matter if you smoke it, eat it, inhale pollen or even touch the plant.

But how do you know if you’re having an allergic reaction to weed?

Pretty simple, if you experience one of the following the next time you use weed, then you’re probably allergic.

Here are the most common marijuana allergy symptoms:

Take note that that the effects of these symptoms can vary, depending on the amount of cannabis you consumed.

For example:

An allergic person who smoked 4 joints can experience more itching than a person who smoked 1 joint.

Even though marijuana allergy usually presents itself with mild symptoms, such as runny nose and watery eyes, there are some unlucky people who get the short end of the stick and get a potentially deadly reaction called anaphylaxis.

Anaphylaxis from smoking weed does happen:

A couple of minutes after ingesting marijuana, an allergic person triggers reactions not just in one spot, but throughout the entire body, setting off a chain of physiological processes that send him into a state of shock.

Anaphylactic shock is life threatening and should be treated ASAP with a shot of adrenaline (Epinephrine).

Learn the signs of anaphylactic shock

Every person should learn to recognize the symptoms of anaphylaxis, smoker or not.

It can happen with just about any allergen and it is an extremely dangerous reaction that requires immediate medical attention. If you know to recognize it, you can get help much quicker and that can save your life.

According to EpiPen, there are 3 approaches to diagnosing anaphylaxis:

First approach:

Skin issues, followed by respiratory problems OR reduced blood pressure.

Second approach:

By having two or more of the following:

Third approach:

Reduced blood pressure after exposure to an allergen. Quick note: you can recognize reduced blood pressure through dizziness.

If you or someone you know fits into any of these categories, call an ambulance right away, because that person is in one bad place.

Thankfully, it all gets resolved in a couple of minutes with a shot of adrenaline — it complements your body’s own adrenaline to reduce throat swelling, open up breathing pathways and regulate blood pressure.

How to treat marijuana allergy

So, after all of this you’re pretty sure that you are allergic to weed?

OK, first, book an appointment with your doctor. An allergist would be a best bet.

They’ll do a skin test and prescribe a therapy, tailored to your particular symptoms. The therapy can involve either medications or completely avoiding any contact with marijuana.

If your allergic reaction to weed is so severe, then you’re need to quit smoking altogether.

However, since I know that most of us like to delay a trip to the doctors as much as possible, you can always use a nasal spray and some antihistamines for treating acute onset of marijuana allergy.

As things are currently, there is really a small number of reported cases of marijuana induced allergies.

But as weed becomes more and more accepted, you can bet that we’ll start seeing more people complaining about allergic reactions to the plant.

Those people will be growers, people who live next to cannabis fields or regular users.

Good news is:

Marijuana is, in the end, a very mild allergen and can be safely consumed by 99% of users.

Unfortunately, there will always be an unlucky few.