Marijuana Allergy: Symptoms, Relief and Prevention (The Complete Guide)

cannabis allergy
By Andrew Ward Updated March 8th

Medically reviewed by Dr. Brian Kessler, MD

Plants can trigger allergies in some people. Cannabis is no different. Symptoms from a marijuana allergy can vary from mild to severe. In extremely rare cases, symptoms could even be life-threatening. 

Read on to learn more about cannabis allergies, including symptoms, possible causes and tips for relief. 

What Causes Marijuana Allergy?

When exposed to cannabis, a person may experience a change in how certain stimuli respond. Known as sensitization, stimuli amplify their response when exposed to specific allergens. This reaction can trigger a range of sensations, from hypersensitivity to, in some cases, trouble breathing.

Various symptoms may arise depending on how the person was exposed to cannabis. Allergic reactions from skin exposure tend to result in rashes, hives or angioedema (swelling). Breathing or inhaling smoke, vapor or plant allergens typically results in agitation to the eyes, nose and throat. 

Certain foods have also been linked to a cross-reactivity effect. Essentially, some proteins or allergens found in cannabis are similar to those found in other plants and foods, like tomatoes, peaches, and hazelnuts. If a cannabis consumer is allergic to one of these foods, it is possible the cross-reactivity could lead to a potentially serious allergic reaction to cannabis. Additional research is needed to fully understand the most likely allergens to cause such an effect.

Marijuana Allergy Symptoms

Since 1963, the medical community has grouped allergic reactions into four categories

marijuana allergy categories
  1. Immediate (type I): The most severe allergic reactions, with symptoms often appearing in minutes or less after exposure. Symptoms can include difficulty breathing, swelling, low blood pressure, blue-hued skin, and shock.
  2. Cytotoxic (type II): Symptoms appear minutes to hours after exposure, triggering various possible cell-damaging antibodies.
  3. Immune complex-mediated (type III): Symptoms take place several hours after exposure, resulting in antigen-antibody complexes and hypersensitivity lasting hours or days. 
  4. Delayed hypersensitivity (type IV): Symptoms take hours or days to develop, with symptoms often appearing in long-term infectious diseases like tuberculosis and fungal infections. 

Cannabis allergy symptoms can range from mild to severe, capable of landing in any of the four categories. The most common mild symptoms include:

  • Hives
  • Itching (Skin, eyes, throat, etc.)
  • Rashes
  • Runny nose
  • Sneezing
  • Swelling
  • Watering eyes
  • Wheezing

Less common but more severe symptoms may arise, including: 

  • Anaphylaxis 
  • Asthma
  • Shortness of breath
  • Swollen eyes

In one reported case, a 33-year-old woman died from anaphylaxis not long after she injected herself with a solution containing boiling water and plant material. Anaphylaxis is a condition caused when the immune system releases natural chemicals that can decrease blood pressure levels and make breathing difficult or impossible. The life-threatening effect tends to appear seconds to minutes after a person is exposed to an allergen. It is typically more common in people with allergies to items like peanuts and bees. Other less severe reactions from anaphylaxis include a weak pulse, skin rash and nausea.

CBD Oil Allergy 

CBD is largely regarded as a safe and favorable cannabinoid, believed to help with various medical and personal needs. However, some people may experience adverse allergic reactions like they would THC or other cannabinoids. Hempseed (a regular source of CBD) may also lead to adverse reactions when ingested. 

CBD oil-based allergy symptoms tend to mirror those of other cannabinoids. Commonly reported symptoms include:

  • Itching 
  • Runny nose 
  • Sneezing 
  • Swollen eyes 
  • Watering eyes

A debate continues to rage about long-term CBD use and dosage. Some have cautioned that regular high doses of 1500 mg daily can lead to adverse effects, including drowsiness, dry mouth and low blood pressure. 

While we may not fully understand the safety profile of CBD or cannabis, we are making progress. So much so that the U.S. Food and Drug Administration (FDA) has approved several cannabis-based medications for various conditions.

  • Epidiolex (CBD)
  • Marinol (dronabinol) (synthetic cannabis)
  • Syndros (dronabinol) (synthetic cannabis)
  • Cesamet (nabilone) (synthetic cannabis)

The FDA stresses that it hasn't approved other medications made from or derived from cannabinoids. The approved drugs are meant to treat specific conditions, including treatment-related wasting syndrome and seizures associated with Lennox-Gastaut syndrome or Dravet syndrome. 

Still, the FDA acknowledges that other cannabis items and products are used to treat various medical conditions, including HIV, AIDS, cancer, and more. The organization highlights programs like its Fast Track, Breakthrough Therapy, Accelerated Approval and Priority Review efforts to get proven medications to the market. However, with cannabis still federally illegal in the U.S., it is uncertain how many other products will receive FDA approval in the near future. 

Marijuana Allergy Diagnosis

A lack of cannabis clinical research has limited our understanding of the plant, including common diagnoses for a cannabis allergy or its side effects. Thankfully, this doesn't mean we are without options. Today, medical professionals typically use one of two testing methods to diagnose a marijuana allergy: 

  • Intradermal/Skin Testing: This relatively non-invasive process has a doctor injecting a diluted allergen into the surface of a patient's skin. If redness, swelling or itching appears in the next 15 minutes, the person may have a cannabis allergy. 
  • Blood Testing: Doctors extract blood from the patient and test it for antibodies. Patients with higher than expected antibody counts are more likely to have a cannabis allergy. 

There are pros and cons to each process. Proponents of blood testing say it may be best since it requires just a single needle prick. However, intradermal advocates point towards the less invasive and more rapid process that comes with a skin test. 

Marijuana Allergy Treatment

There don't appear to be many, if any, treatments specifically focused on cannabis allergies. That said, there is quite a bit of promise surrounding the subject. And in the meantime, some general allergy treatments have reportedly worked on some individuals. 

As a 2020 Allergy, Asthma & Clinical Immunology analysis noted, cannabis allergens act identically to other allergens. Researchers stated that existing treatments could help treat cannabis allergy symptoms. These existing treatments include: 

  • Antihistamines: Antihistamines are believed to play an integral role in improving the quality of life for numerous allergy patients. Antihistamines can be found at pharmacies as over-the-counter or prescription options. 
  • Intranasal corticosteroid sprays: Like antihistamines, intranasal corticosteroid nasal sprays help make breathing easier by reducing swelling and minimizing mucus in the nasal cavity. You can find nasal sprays at pharmacies as over-the-counter or prescription options.
  • Ophthalmic antihistamine drops: Administered to the eye, ophthalmic antihistamine drops may relieve a person's eye and nose allergy symptoms. You can find eye drops at pharmacies as over-the-counter or prescription options.

Marijuana Allergy Prevention

At this point, experts suggest that the best way to avoid a cannabis allergic reaction is to do the same thing you would with any other allergen: avoid them. 

That tip is easy enough to follow on paper, but what about in practice? For the thousands – if not millions – of cannabis consumers and industry workers, the question remains: what can you do about cannabis allergies? Unfortunately, there aren't any surefire solutions at this time. 

But don't fret. There are options you can put to use. And while these steps won't completely resolve the problem, they may help minimize the issue for you or anyone nearby who suffers from a cannabis allergy: 

Avoid Contact When Consuming: If someone in your group is allergic to cannabis, consider moving the consumption to another space, so that person can breathe more easily. If you have nowhere else to consume, kindly ask the person if they'd mind moving for a few minutes, but be aware that you're still likely putting them out by asking. 

Get Good Ventilation: Keeping the air flowing should help reduce the problem to some degree. Strong fans, open windows and air purification systems can all help reduce the amount of cannabis smoke you’re breathing in.

Clean Up After Consuming: Don't leave any cannabis remaining after your session. Do your best to clean the surrounding area. Then do the same for the air. Essentially, do your best to ensure the allergens are out of the room. 

Consider Face Masks and Gloves: Gloves and masks can help keep exposure and allergen transfers low. Since COVID has been around, it’s become much easier for the average consumer to find and purchase masks and gloves to use. 

Have Medication On Standby: Be prepared for the worst case with some of the treatment options listed above or other doctor-recommended treatments. 


There is still a lot to learn about marijuana allergies. 

Allergic sensitization has been understudied for years. Cannabis prohibition is undoubtedly to blame. So too is the lack of reported cases. Until recently, the public didn't report such symptoms for various reasons, ranging from legal concerns to possible embarrassment. However, there is nothing to be ashamed of if you experience symptoms due to cannabis. 

We are likely to learn more about cannabis allergy symptoms, causes and possible treatments as we obtain more peer-reviewed studies. Such studies will likely focus on specific consumer groups, including potential effects on teens and people using cannabis while undergoing chemotherapy. 

The information in this article and any included images or charts are for educational purposes only. This information is neither a substitute for, nor does it replace, professional legal advice or medical advice, diagnosis, or treatment. If you have any concerns or questions about laws, regulations, or your health, you should always consult with an attorney, physician or other licensed professional.

You might also like: