Cannabis (marijuana) may be an important allergen in young people

Cannabis, also known as marijuana, is the illicit drug most widely used by young people in higher-income countries. Allergy symptoms have only occasionally been reported as one of the adverse health effects of cannabis use.

This Spanish study included 340 patients who were cannabis users, with mean age 27 years.

The participants were selected from a database of 21,582 individuals with asthma, sensitized to pollen; and others sensitized to tobacco, tomato and latex, considered as cross-reacting allergens.

Among the marijuana users, 61% of males were sensitized to cannabis.

72% of the patients allergic to tomato were sensitized to cannabis, but a positive specific challenge to cannabis was highest in patients sensitized to tobacco (62%).

Pollen allergy was not a risk factor for cannabis sensitisation.

Prick tests and IgE for cannabis had a good sensitivity (92 and 88%, respectively) and specificity (87 and 96%) for cannabis sensitisation.

Cannabis may be an important allergen in young people. Patients previously sensitised to tobacco or tomato are at risk. Cannabis prick tests and IgE were useful in detecting sensitisation.


Allergic hypersensitivity to cannabis in patients with allergy and illicit drug users. Armentia A, Castrodeza J, Ruiz-Muñoz P, Martínez-Quesada J, Postigo I, Herrero M, Gonzalez-Sagrado M, de Luis D, Martín-Armentia B, Guisantes JA. Allergol Immunopathol (Madr). 2011 Jan 25.

Low-dose Marijuana Exposure Improves Pulmonary Function Over 20 Years, claims JAMA, 2012. Were data reliable?

Marijuana - In Focus - The Atlantic -  16 states currently allow the use of medicinal marijuana

Allergic reactions to cannabis (marijuana) - AAAAI Ask the Expert, 2012.

Image source: Cannabis, common hemp. Wikipedia, public domain.

Comments from Facebook:

Matthew Bowdish: "We have seen several patients with cannabis allergy who are involved in the medical marijuana industry. No great tests but their histories are quite suggestive. Insert MJ-IT joke here."

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