According to Purvi Parikh, MD, an allergist and immunologist with the Allergy & Asthma Network, symptoms of a cannabis allergy can resemble those of any other allergy, really, which makes them difficult to peg as reactions to weed in particular. Dr. Parikh says that having allergies to dust mites, mold, pollen, and animal dander increase your chance of being allergic to cannabis, but that doesn't really help narrow things down. At the moment, it's pretty unclear how many people deal with this specific allergy.
In addition to a stuffy nose and sore throat, sufferers may experience itchy eyes, a runny nose, or tickling, itching throat. Those who have a topical allergy may get a rash or break out into hives if the plant touches their skin. Dr. Parikh adds that more severe reactions can include coughing, wheezing, difficulty breathing, or even anaphylaxis, in which multiple parts of your body are affected by allergy symptoms at once, leading to a potentially life-threatening situation. (For the record, Tania Elliott, MD, an allergist and immunologist at NYU Langone, notes that there has been one case of fatal anaphylactic reaction due to cannabis, in which someone intravenously injected themselves with a solution containing cannabis and subsequently died.)
According to Dr. Parikh, it's actually quite difficult to diagnose cannabis allergies. For one thing, someone may have a reaction when smoking weed, but they're actually reacting to mold or dust mites in their buds and not the Cannabis sativa allergens. And, if you already have asthma, smoking weed may exacerbate that condition without triggering an allergic reaction. You'll still feel crummy, but it won't be because of the weed, exactly.
Adding to the difficulty of diagnosing is the fact that there isn't a commercially available skin or blood test for cannabis allergies at the moment. Dr. Parikh says some researchers have created their own skin or blood tests for studies. But, usually, allergists will have to make the diagnosis clinically, by observing their patients' specific symptoms when their skin is exposed to an actual cannabis plant as well as their personal medical histories, explains Dr. Elliott.
Even if there was a clear-cut, mainstream method of diagnosis, the wider medical community still wouldn't have exact stats on how many people suffer from cannabis allergies. Dr. Parikh says it's likely not everyone who believes they may be allergic to weed will feel comfortable bringing it up with their doctor.
If you think you might be allergic to cannabis, you're best off avoiding it, Dr. Parikh says: "We have medications to treat reactions that result from marijuana, but you should avoid it if you are allergic, as subsequent reactions can get worse." Luckily, there are plenty of other ways you can unwind after a long day.
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