Allergy season is upon us. In addition to ragweed and mold, allergy sufferers might also have to watch their exposure to marijuana, say the authors of a study published in Annals of Allergy, Asthma and Immunology.

According to study authors Dr. Thad L. Ocampo and Dr Tonya S. Rans, cannabis - like other pollen-producing plants - usually starts shedding pollen in late summer and early fall, causing inflamed nasal passages, sneezing, congestion, itching and a runny nose in allergy sufferers.

"Cannabis pollen grains are very buoyant," they write, "allowing for distribution across many miles," which means that an outdoor grow a few miles away could, conceivably, cause allergic reactions for folks in the near vicinity.

Many people test positive for a marijuana allergy

But skipping through marijuana fields obviously isn't the only trigger for allergic reactions to marijuana. According to the study, nearly 15 percent of people who smoked marijuana tested positive in a skin prick test to determine allergic sensitivity - and that percentage jumped to 18.2 percent among those who reported frequent and/or regular use.

"A positive association also was noted between Cannabis smoking, plant handling, and sensitization," according to the study authors, with the highest level of positive skin prick testing results in self-reported "habitual and dependent users" compared with "experimental or occasional users."

By contrast, only 5 percent of nonsmokers tested positive for a cannabis allergy, suggesting that regular exposure can make you more likely to develop an allergy.

Weirdly, more potent marijuana could also be contributing to the rise of cannabis allergies.

"The potency of C sativa, often measured by THC content, has increased over the years, with some Japanese strains of sinsemilla containing as much as 22.6% THC," according to the study author. "This could play a role in allergic disease because THC has been suggested as a pertinent Cannabis allergen."

Only two patients report symptoms

It's worth noting, however, that only two of the patients reported actually having allergic symptoms, which researchers noted "highlight[s] the challenge of correlating diagnostic results with allergic disease." In other words, just because you test positive for a cannabis allergy doesn't mean you swell up like a balloon every time you get high.

The study authors also recognized that the laws around cannabis mean we're unlikely to get an accurate picture of how many people are actually getting sick from smoking marijuana - as well, they point out, "the legal limitations to obtaining, preparing, and using extracts can pose diagnostic challenges" for allergists, who can't can't access the materials they need to test patients for cannabis sensitivity without jumping through endless legal hoops.

If you think you might be allergic, "symptomatic treatment with antihistamines, intranasal steroids, and nasal decongestants" is recommended to treat sneezing and stuffy noses associated with smoking. But ultimately, if you really think you've got a serious weed allergy, you're advised to treat it the same way you would a sensitivity to wheat, or cat dander or peanuts: simply stay away.