Can You Be Allergic to Weed?

Plant, seasonal, and food allergies are becoming more and more prevalent as the rate of people with allergies has more than doubled in the past 60 years, from 3% of the population in 1960 to around 7% in 2018, and the number is likely to increase in the future. Apart from these common allergies, people are developing allergies to the strangest things, like this woman who is allergic to water, which makes you wonder what else are people allergic to.

As marijuana use is increasing all over the world and consequently the legalization laws as well, some people wonder whether you can have an allergic reaction to marijuana. In this article, we’ll give you all the research on whether marijuana allergies exist, as well as the common symptoms and signs that would indicate a cannabis allergy after ingestion, inhalation, or topical application of weed.

Can You Have an Allergic Reaction to Cannabis?

While the research on this subject is fairly new, marijuana allergies do exist similar to how people are allergic to a lot of plants and pollen. As cannabis is becoming a widely used drug for both medical and recreational purposes, there has been an increase in the number of reports of cannabis allergies. There are even people who report being allergic to the cannabinoid cannabidiol (CBD) which they noticed after consuming CBD oil.

The American Academy of Allergy, Asthma, and Immunology (AAAAI) claims that some people may develop an allergic sensitization or an allergy to cannabis after exposure through:

• Smoking cannabis;
• Eating cannabis;
• Touching cannabis;
• Inhaling cannabis in the air.

According to research done in 2020, Cannabis Sativa is especially irritating for some people.

The 411 on Cannabis Allergies

While we’ve talked about the benefits and side effects of cannabis consumption in a number of previous articles, we’ve yet to discuss cannabis allergies and the mechanisms that cause allergic reactions to marijuana in some users.

Lipid Transfer Proteins (LTPs)

One of the major cannabis allergens, according to a 2019 study published in The Journal of Allergy & Clinical Immunology, is the lipid transfer proteins (LTPs) found in weed. The study was done on 62 healthy control subjects and 120 cannabis allergy patients who were given a hemp extract in a skin-prick test, as well as two more tests. The study showed that 80% of the patients showed a sensitivity to the LTPs, which triggers an allergic reaction when taken in larger doses leading to the overproduction of antibodies.

Cross-Reactivity

An allergic reaction to cannabis is more likely in patients who have cross-reactivity to other plants that contain similar proteins to cannabis according to the 2017 study. Furthermore, a 2008 study concluded that subjects sensitive to tomato allergens were also likely to be sensitive to cannabis. 

Apart from tomatoes, other foods that have proteins that resemble cannabis proteins and may cause an allergic reaction include:

• Peaches;
• Grapefruit;
• Eggplant;
• Chestnuts;
• Bananas;
• Apple;
• Almonds.

Another small-scale 2018 study concluded that people who are already allergic to molds, plants, dust mites, and cat dander are more likely to develop a cannabis allergy, although more research is needed.

In rare cases, marijuana can even cause anaphylaxis in just a few minutes after the exposure to the allergen which may lead to coma or death, so you should get to the ER immediately if you suspect this. Common anaphylaxis symptoms include:

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

Terpenes

Apart from the LTPs, terpenes are also a common cause of a cannabis allergy. While terpenes have a lot of medical benefits similar to the cannabinoids found in weed (CBD, THC, and others), they may also cause an allergic reaction. Terpenes such as linalool, limonene, and other prominent terpenes found in weed can trigger an allergic reaction when oxidized or exposed to the air. (Andersen et al, 2016; Christensson et al, 2010)

The Symptoms and Types of Marijuana Allergies

According to immunologists, the increase of reported cases of cannabis allergies is due to the increase of people exposed to cannabis. The ingestion, inhalation, or topical application of hempseed, cannabis, and other cannabis products can trigger a cannabis allergy which you’ll be able to spot if you take a look at the following symptoms.

Skin Contact

The most common marijuana allergy is caused by direct contact between the skin and the plant or its flowers, and the most common symptoms include:  

• Dry, scaly skin;
• Itching;
• Rash;
• Redness.

In rare cases, handling cannabis can cause contact dermatitis and the following symptoms:

• Dry skin;
• Blisters;
• Hives;
• Itchiness;
• Red, inflamed skin.

Airborne Exposure

Similar to the pollen of other plants, cannabis pollen can be an allergen even when you breathe it secondhand, and the most common symptoms include:

• Rhinitis (itchy, runny nose);
• Itchy, watery eyes;
• Nasal congestion;
• Respiratory problems;
• Sore throat;
• Sneezing.

Symptoms can sometimes be similar to the seasonal allergy symptoms.

Consumption

Cannabis edibles such as weed brownies have become more popular in recent years and with that rates of people developing a weed allergy have also increased. The common symptoms that indicate an allergy to weed after consumption include:

• Difficulty speaking;
• Eye redness or swelling;
• Hives or rash;
• Skin swelling;
• Shortness of breath.

How to Diagnose a Cannabis Allergy

Similar to how you would get tested for other types of allergies, you’ll either get a skin prick test or a blood test.

Skin Prick Test

Following a physical examination from your doctor, you’ll be asked to take a skin prick test which means the doctor will apply the diluted allergen on your skin by pricking it with a needle. Users who develop redness, itching, or a red bump in the next 15 minutes may be allergic to the allergen.

Blood Test

You can also detect marijuana plant allergies through a blood test. The sample of blood is tested for the presence of antibodies to cannabis and the people who have more antibodies than expected are more likely to be allergic to cannabis.

What to Do if You’re Allergic to the Cannabis Plant?

Because there’s no specific treatment for a marijuana allergy, the less serious symptoms are treated with common allergy treatment methods such as antihistamines, nasal sprays, or epinephrine injection (EpiPen) for more severe allergies and people at risk of developing anaphylaxis. Other treatment includes a course of allergy shots in order to reduce the sensitization to the substance.

Since you can’t do anything specific about the allergy, your best bet is to avoid marijuana altogether. People who are allergic to weed should avoid using medical marijuana and seek alternative treatment. Medications such as Epidiolex, Marinol, Syndros, and Cesamet that contain CBD should also be avoided by people who have allergies to cannabis.

Most people who are allergic to marijuana will actually have a reaction that is similar to a reaction to seasonal allergies and won’t experience life-threatening symptoms. However, if you do avoid cannabis, you’re generally safe unless you’re exposed to cannabis via airborne exposure. If you think that you may be allergic to cannabis, it’s always a good idea to get tested so you know what steps you need to take in the case of accidental exposure.