Unlike alcohol and hard drugs, there’s no evidence that smoking weed can kill you directly. But a recent study published in the Annals of Allergy, Asthma & Immunology brings a new potential issue to light: cannabis allergies. While being allergic to weed is quite rare, the authors state that it’s an issue that may gain more importance as the weed legalization movement sweeps across the country, exposing more people to the drug than ever before.

The researchers, hailing from the American College of Allergy, Asthma, and Immunology, focused primarily on the sativa strain of marijuana — which produces more of an energetic, cerebral “daytime high” than the indica strain (which is typically associated more with sleepiness and relaxation). They found that among people who had allergies to sativa, symptoms varied from asthma and eczema to anaphylaxis, or the most severe type of allergic reaction that could lead to death.

In the study, the researchers examined several cases in which people either handling or smoking marijuana showed allergy symptoms. In one case, a 28-year-old who handled weed exhibited sneezing, hives, and swollen eyes afterward — and was later diagnosed with a cannabis allergy. Another case outlined a person who went into anaphylactic shock after consuming hemp seed-encrusted seafood (and a seafood allergy test proved negative).

It’s possible that cannabis allergy cases will increase as weed legalization becomes more prevalent. And unlike people who have food allergies, patients with cannabis allergies would be at a higher risk of being exposed to secondhand marijuana smoke that could irritate them.

“With state laws allowing medical and in some cases recreational use of marijuana, there is a growing potential for legitimate personal and commercial exposure,” the authors write. “The evolving legal status of [cannabis], its highly prevalent use throughout the world, and the varied forms in which it is used could translate into its growing role as a clinically relevant allergen that might be encountered.”

There hasn’t been much medical literature about marijuana allergies, although a 2014 study by Belgian researchers found similar results. But it shouldn't come as a shock. Besides, there are allergies for almost everything — including, of course, tobacco smoke and even alcohol (though it’s typically referred to as an “alcohol intolerance”). These allergies are extremely rare compared to peanut or shellfish allergies. Likewise, cannabis allergies are rare and shouldn’t prevent marijuana legalization from moving forward; there are people who are allergic to medications (penicillin allergies, for example), and marijuana allergies should be viewed the same way.

The authors of the study conclude that more research will be needed before people should start worrying about developing weed allergies.

Source: Ocampo T, Rans T. Cannabis sativa: the unconventional ‘weed’ allergen. Annals of Allergy, Asthma & Immunology. 2015.