SFGate Blogs: Marijuana allergies confirmed but poorly understood

Posted on March 6, 2015 at 9:31 am by David Downs in Growing MarijuanaHealth

Cannabis allergies are a real, if little understood condition, two Texas researchers conclude.

Talk about a buzz-kill.

As cannabis becomes more legal, be prepared for an increase in people saying they’re allergic to the once-illicit herb.

That’s the conclusion of two Texas researchers published in the Annals of Allergy, Asthma and Immunology. While highly uncommon and little understood, a marijuana allergy can — in theory — cause itching, sneezing, runny nose and even anaphylactic shock.

People can be allergic to cannabis pollen, similar to other pollen allergies, and some are allergic to popular foods made with hemp seed. One patient ate “hemp seed–encrusted seafood (and tolerated a subsequent oral seafood challenge) and required antihistamine and epinephrine treatment.”

Other folks might be allergic to THC, the main active ingredient in cannabis, “Nevertheless, a single unifying allergen among reported cases has not been discovered,” researchers state.

Allergists can test for cannabis allergy by pricking a patient’s skin with a pot extract, but it’s a dark art. “Differences in source material and extraction techniques can introduce significant variability,” and so can “contaminants, additives, and inherent variability in the native allergen extracts.”

There are no “reliable standardized diagnostic testing options” for a pot allergy and “often poor correlation between testing and true clinical allergy”. And most allergists can’t legally obtain cannabis to test for an allergy.

Potential pot allergy treatments are analogous to other allergies: avoid the allergen, take antihistamines, intranasal steroids, and nasal decongestants, and give epinephrine auto-injectors to people with a history of anaphylaxis.

And of course, researchers need more money for more research: “Much research is still needed to more definitively define pertinent allergens, develop a standardized extract, establish diagnostic sensitivity and specificity, and clarify treatment options for clinically affected Cannabis-allergic patients.”