Case Study: Secondhand Marijuana Smoke in a Child with Severe Asthma

The following case study was presented at the American College of Asthma, Allergy and Immunology annual meeting in Seattle, Washington.

Introduction: Secondhand cannabis exposure is expected to increase significantly as personal cannabis use becomes legalized in more states and countries. Cannabis allergy from firsthand use has been reported in adults but allergy in young children exposed to secondhand smoke has not been previously reported. We present a case of cannabis allergy associated with secondhand cannabis exposure and highlight its potential impact on childhood asthma.

Case Description: A 6-year-old boy with severe asthma was poorly controlled on a regimen of high-dose inhaled mometasone/formoterol, inhaled tiotropium, and montelukast. Additional history-taking revealed that family members were frequently smoking cannabis in the household, and his maternal grandmother reported a history of urticaria after personal use of cannabis. Skin prick testing to a cannabis puddle (in saline) resulted in wheals of 9 £ 8 and 15 £ 8 mm for patient and grandmother respectively, while a control individual was negative. We then performed a basophil activation test in which the patient demonstrated significant activation to cannabis. After removal of cannabis from the home environment, the patient's asthma improved by subjective (Asthma Control Test questionnaire) and objective (impulse oscillometry) measures.

Discussion: There have been several reports associating cannabis use with allergic symptoms including rhinitis, conjunctivitis, asthma, and anaphylaxis. This is the first report of cannabis allergy in a young child and suggests that exposure to secondhand marijuana smoke may contribute to difficult-to-control asthma in such children.

According to study author Bryce Hoffman, MD, of New York-Presbyterian Hospital in New York City, New York, the case study suggests that it’s possible for both children and adults with uncontrolled asthma to find their symptoms worsening due to cannabis allergy and exposure to marijuana smoke.

“A 6-year-old boy suffering with severe asthma had family members who frequently smoked marijuana in the house,” Hoffman said in a statement. ““Even though family members didn’t smoke marijuana in the same room as the child, he was exposed to traces of smoke and plant material. It was not clear why his asthma was so severe and not responding to aggressive asthma therapies until we determined he was allergic to cannabis. After the cannabis was removed from the house, his asthma improved.”

In the case study, Hoffman also found that the subject’s grandmother had a history of urticaria that followed her personal use of cannabis.

“Although the boy didn’t have any clear allergic symptoms such as hives — like his grandmother – we know indoor allergens like pets and dust mites can make asthma worse without obvious allergic symptoms,” Hoffman said. “This is different from secondhand tobacco smoke, which worsens asthma by irritating the lungs in a non-allergic way. The takeaway is that cannabis allergy can make asthma worse even without direct use. Anyone using cannabis needs to consider that others living in their house who have asthma – particularly children – may be at risk of uncontrolled asthma.”

The case study, titled Cannabis Allergy in a Young Child With Severe Asthma Exposed to Secondhand Marijuana Smoke, was presented at the annual meeting of the American College of Allergy, Asthma and Immunology in Seattle, Washington.