Exposure to marijuana smoke can lead to allergic reactions in some people, says a study. According to reasearchers, Marijuana, like other pollen-bearing plants, is an allergen which can cause allergic responses.

"Among other things, cannabis pollen or cannabis smoke exposure has resulted in symptoms of allergic rhinitis (hay fever) conjunctivitis and asthma," said Thad Ocampo from Wilford Hall Ambulatory Surgical Center, San Antonio, Texas.

The researchers have cited case reports regarding episodes of allergic reactions, hypersensitivity and even anaphylaxis (a severe allergic reaction) to cannabis in its various forms.

Allergic asthma triggered by seasonal and occupational exposure to cannabis has also been reported. Cannabis’ legal status may create barriers for accurate and clear patient reporting, and that legal limitations may pose diagnostic challenges, said the authors.

The study was published in the journal Annals of Allergy, Asthma and Immunology.