by Seshata on 08/02/2013 | Consumption

Is it possible to be allergic to cannabis?

Anecdotally, reports of so-called “THC or cannabis allergy” abound. This reaction is characterised by a red, prickly rash over exposed skin, often accompanied by mild to moderate respiratory irritation (often including coughing and sneezing), and is occasionally found among those who work in close contact with the growing cannabis plant.

Hemp protein powder and vomiting

One individual who claimed to suffer such a rash (presumably a form of urticaria or contact dermatitis) after handling cannabis plants also reported suffering an acute bout of vomiting after consuming hemp protein powder as an exercise supplement. The individual had previously consumed many other forms of protein with no ill effects.

There are other instances of vomiting occurring after consuming hemp protein, but it is not clear if there is a relationship between the two phenomena. Aside from an allergen within the hemp protein powder itself, it is possible that poor storage, contamination or added ingredients (such as chlorella) may contribute to such cases.

Sensitivity arises from contact with both male & female plants

Is it possible to be allergic to cannabis

The substance that causes sensitivity and adverse reactions in growers and plant workers may well find its way into hemp protein powder too. It is certainly not a phenomenon solely related to male pollen, as many plant allergies are, as it occurs in male-free grow-rooms.

However, research into allergic response in Midwest U.S. populations, where wild cannabis is widespread, indicated that the pollen itself may cause or exacerbate symptoms of rhinitis in sensitive individuals. It is difficult to distinguish between reactions due to cannabis pollen and those from other allergens, but skin-tests also showed that 61% of patients exhibited sensitivity.

The problem is also associated with handling the dried plant matter, and occasionally smokers (even those who are not in contact with the growing plant) experience symptoms during consumption. Many sufferers also report handling cannabis for prolonged periods with no difficulty prior to experiencing sudden and acute symptoms.

Phytodermatitis is a well-known phenomenon

Is it possible to be allergic to cannabis

Many plants cause allergic contact dermatitis in humans – in fact, the term phytodermatitis specifically refers to plant-related reactions.

Poison ivy, oak and sumac are well-known examples of such plants and affect the majority of humans. Although some claim to be immune, it is not clear if these are cases of true immunity or whether the allergic response is somehow delayed or modified.

Stinging nettles too cause contact dermatitis. Indeed, the term urticaria derives from the scientific name for this species (Urtica dioica), although this term also applies to hives, which may arise due to a variety of causes not limited to plants.

U. dioica is quite closely related to the cannabis plant: both the Cannabaceae and the Urticaceae families are thought to belong to an informal clade within the Rosales order known as the urticalean rosids.

Stinging nettles cause irritation by introducing histamine to the epidermis: the thousands of tiny hairs (known as trichomes, as with cannabis and many other plant species) that cover the surface of every leaf penetrate the outer layers of the skin and inject histamine, along with formic acid and serotonin, directly into the skin. As cannabis has such similar trichomes, it is possible that they contain a mixture of similar irritants.

Histamine & the immune response

Histamine is an organic compound comprised of nitrogen and hydrogen, and is synthesised in the body by the metabolism of the amino acid histidine. Histamine has a vital role in regulating the immune response. When allergens are present at certain key areas of the body (such as the mucous membranes), histamine is released by mast cells or white blood cells known as basophils in a process known as degranulation.

Degranulation is a mechanism whereby certain cells involved in immune response release cytotoxic compounds that destroy invading microrganisms such as allergens. When such allergens enter the body, the molecules of the free-floating antibody protein known as immunoglobulin E (IgE) bind to Fc receptors found on the surface of the mast cells and basophils.

The allergens then bind to the IgE, and the cell begins to release histamine. This triggers the inflammatory response and increases the permeability of the capillaries to allow certain white blood cells and proteins to directly attack the invading pathogens.

A case of cannabis allergy triggering cross-reactivity in other plants

Is it possible to be allergic to cannabis

However, allergic reactions to cannabis may not be entirely due to histamine, although it is likely to be involved. In one notable case, a 28-year-old man with no previous allergic symptoms reported contact urticaria after handling cannabis plants, and was subsequently forced to cease consumption of cannabis after smoking the drug caused rhinitis-like symptoms, swollen eyelids and itching.

Months later, the patient began to experience anaphylaxis after consuming tomato, pepper and fig, contact urticaria on handling peach peel, and oral allergy from apple, almond, eggplant, and chestnut. Skin tests were positive for cannabis, apple, peach, and tomato.

Can s 3, the proposed cannabis allergen – Is it possible to be allergic to cannabis?

Immunodetection procedures indicated that a lipid transfer protein (LTP) was responsible: LPTs, as the name implies, are responsible for transfer of lipids and other fatty acids across cell membranes, and are often implicated in serious food allergies. Further testing yielded an isolated protein believed to be the cannabis allergen, which the researchers named Can s 3.

Reports of extreme symptoms resembling anaphylaxis or acute asthma are rare but do occasionally occur. Such cases usually report that any contact with the plant in any form (even hemp lotion or clothing) causes a reaction serious enough to require constant access to an epi-pen.

So, is it possible to be allergic to cannabis? Without further empirical evidence, it is impossible to determine whether these severe reactions are entirely due to an allergen in cannabis, or if other environmental or even psychological factors exert an influence. However, the research into the Can s 3 protein points to the existence of a true allergen, and those suffering from common food or plant allergies may note a degree of cross-reactivity.

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Clarisa Robishaw

Symptoms of allergic rhinitis resemble a cold, but they are not caused by a virus the way a cold is. When you breathe in an allergen, your immune system springs into action. It releases substances known as IgEs into your nasal passages, along with inflammatory chemicals such as histamines. Your nose, sinuses, or eyes may become itchy and congested. Scientists aren't sure what causes your immune system to overreact to an allergen."


melva smith

So glad to see this article. I tried to eat some of those packaged hemp hearts for health reasons and i swole and got a prickley hivey sensation all over. I felt strange too and my throat became puffy and irritated. If exposed while walking past hemp smoke, i break out in hives. So glad that some of the hud housing properties are banning smoking i general in apartment units. People have to go outside. I cant imagine the living misery this stuff would put a person through if an inconsiderate neighbor refused to take it outside. Praises to HUD.



I got an Oral Allergy Syndrome (OAS), which is an aggravation of Allergic Rhinitis, not from cannabis use but from several years of taking Prozac (fluoxetine) and other prescribed drugs. I tried different brands of fluoxetine and I always got the OAS on the sixth day. At the same time, due to fluoxetine and the other prescribed drugs, I got allergic to most Non-steroidal anti-inflammatory drugs, complex B and penicillin.

As you know, to avoid the OAS, all raw vegetables and fruits have to be cooked in order to modify the lipid transfer protein (LTP) which is confused by our body with a protein from pollen so in order to avoid an allergy from cannabis pollen, you have to decarboxylate your cannabis (turning ATHC into THC), in other words you have to cook it (cookies, brownies, butter, etc) and eat instead of smoking it or vaporize it. This is the only way I was able to stop getting allergies and Asthma from cannabis. At least, that is my experience.

But be careful when you eat cooked cannabis because you can get temporal or permanent psychosis since THC taken by mouth undergoes “first pass metabolism” in the small intestine and liver to 11-hydroxy which is four times more psychoactive* than unmetabolized THC, and four times more immunosuppressive

Great article btw :)

*Source: Cannabis and Cannabis Extracts: Greater Than the Sum of Their Parts?



Very insightful. I have a relative experiencing some of these symptoms, who had initially thought it was a food allergy. She recently picked up cannabis after years of not smoking. I have a feeling this is it.


Rainy Woods

I have a severe allergic reaction to flowering mj plants. When I harvested last year I was covered in tiny itchy red fire bumps on face, ears, neck, forearms and hands. I thought it was spider mite bites, but again this year when I harvested the same thing happened and plants were mite free. Sadly I am allergic to fresh flowering mj. The dried doesn't affect me at all. I am so miserable I want to rip my face off, it isn't worth ever growing mj again.


Pierre T

I am sure we could get people to try out their allergies or contact dermatitis with the different strains and we would find a strain or many(i hope for this) where there are no reactions.
I know i would like to buy seeds for this strain if there are chances that i would not react to it as i suffer from contact dermatitis. If you have found strains where the reaction is minimal please let us know.




White Widow lineage I can't even touch it get hives. Anything like that gets me



I agree it happened to me with a particular strain. I have handled many strains but today new strains, and I got an awful blistering rash on one arm, my right one which I am right handed. It was dry but I really think its a particular strain that did this and I can only narrow it down to lemonade, berry wreck or skunk #1 because those are the strains I worked with today. I handled air dried and freeze dried. It is as bad as poison ivy but not spreading. Id like to go get a shot if I wasnt a cheap ass! It is nearly that bad



Nice blog.


Ellen Smith

I never heard of such cases of allergy especially due to cannabis. This is new information for me. However, allergic reactions to cannabis may not be entirely due to histamine, although it is likely to be involved.



At the end of august this year, my flowers were changing from babies to actual sticky, beautiful flowers. I do have fall allergies so I chalked up my symptoms to be that. However any over the counter antihistamines have not worked. So I thought, maybe a head cold. I harvested one of my girls last night and upon waking up, my symptoms have doubled at the least! Itchy, watery eyes, very red, runny nose, severe sinus pressure,sneezing cough or sore throat though. Am definitely considering the fact that I may be allergic to flowering marijuana. It doesn't bother me until it's in full flower, I do wear gloves and a long sleeve shirt, so no itchies. I think I will try a medical mask in addition to my harvesting wardrobe!



Great article. Thanks for the info. I too suffer from this allergy and when it's time to harvest I glove up and cover up as much as possible. Once it's all jarred up I'm fine and since I started vaping instead of smoking thats helps.



Unfortunately, After growing for over a year I have developed an allergy to my plants. My hands get red rashes and raised filled blisters. Talk about unsightly, painful and inconvenient. So, whats a girl to do?
Cover up head to toe. Double the gloves. 5mil nitrile is not enough. Somehow the trichomes/hairs penetrate them. Vapor Respirator when flowering. Only my hands suffer so I try to be extra careful.

What did you think I was gonna do? Stop growing? No
Theres ways around everything. .Just gotta find it. HAPPY GROWING



What a out mj salve? Friends gave us a jar to try out. I have fibromyalgia so I tried it on the places hurting the most... Hands, elbow, tail bone/butt crack area. Few days later I have a red bumpy itchy rash in the tail bone/butt crack area. I'm freaking out, I haven't got my legal card yet so I can't go to the doctor. But now my scalp and thighs are itchy too, along with my eyes! And I never get allergies. But 3 years ago I had a rash that lasted for a year. They finally figured out the name of it but not what caused it. So... Does anyone think my butt crack rash could be caused by the mj salve? No rash on hands or elbow. Please I'm desperate. Thank you.



Toured large cannabis Farm yesterday. Each time we passed outside greenhouse containing plants with buds my tongue, lips, and face began to tingle. I am allergic to soy, in particular soy reaction to cannabis was akin to that of soy. We were given bottle of commercially made medicinal cannabis pain cream 30 mg THC. Within 4 minutes of applying to upper arms for pain, I was scrubbing it off, dizzy, and felt as if I was having a reaction to soy but 10-fold in severity. My ears throbbed, had cotton mouth, face felt as if I had severe sunburn, joints really hurt. Whole event lasted 2+ hours.


Pauline Emery

I started taking cannabis tincture a few weeks ago, starting with two drops in a spoon of water by mouth. I certainly felt something happening the first night and I felt a tingling on my face and throat and awoke with a very dry mouth. At first I thought this meant that good things were happening but now I think it might be an allergic reaction. I graduated to four drops at night and now I've developed a really bad case of an excema like rash on my face, which itches and burns horribly. I thought it was due to gluten in my diet (I know I'm sensistive to this) but it's actually become worse. After reading the above comments, I'm going to stop the tincture for a while and see what happens.. Rather disappointed as I was really hoping to reduce inflammation in my body and I know cannabis can do that.



This is very much my experience! I smoke for my pain for brittle bones disease (Bruck Syndrome) andhave developed severe rhinitis and now raised itchy white bumps with contact.
Cannabis helps me greatly for my pain — I do have respiratory discomfort daily as a result of rhinitis. I try to vape most often (no access to edible,) but I do love my joints! I’m worried though, should I be concerned about anaphylactic shock? I don’t have any other allergies to fruits and this is the only severe allergy i have other than the occasional seasonal allergies. Please advise?


Scarlet Palmer

Hi there,

Thank you for your comment. We are sorry to hear about your situation. As Sensi Seeds is not a medical agency or practitioner, we cannot give any kind of medical advice other than to consult our registered healthcare professional. This article about the potential benefits of medicinal cannabis might be useful for you to show your healthcare provider if they are not familiar with it.

You may also find it helpful to contact a support group for medicinal cannabis patients. In the UK there is the United Patients Alliance, and throughout much of the rest of the world there is NORML, who should be able to put you in touch with a group in your area (search United Patients Alliance or NORML followed by your area name).

This are our pages on medicinal cannabis and medicinal cannabis strains, which you might also find interesting.

With best wishes,




This is very much my experience! I smoke for my pain for brittle bones disease (Bruck Syndrome) andhave developed severe rhinitis and now raised itchy white bumps with contact.
Cannabis helps me greatly for my pain — I do have respiratory discomfort daily as a result of rhinitis. I try to vape most often (no access to edible,) but I do love my joints! I’m worried though, should I be concerned about anaphalyla


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