A 6-year-old boy with severe asthma wasn't responding to the usual treatments. It was only when family members stopped smoking marijuana at home that his breathing got better, according to his doctor.
The boy's case shows that exposure to secondhand pot smoke can worsen asthma in children who have a marijuana allergy, a new study reports.
The child's relatives frequently smoked marijuana in the house, said Dr. Bryce Hoffman, lead author of the report.
"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," explained Hoffman, an allergy and immunology specialist in Denver.
"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," Hoffman said in a news release from the American College of Allergy, Asthma and Immunology (ACAAI).
The case study also said that the boy's grandmother had a history of hives after personal use of marijuana.
"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 type of trigger is different from secondhand tobacco smoke, which worsens asthma by irritating the lungs in a non-allergic way, he explained.
"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," Hoffman said.
Asthma is a chronic respiratory condition. If you have asthma, your airways become inflamed and swell, making it difficult to breathe.
The study was presented recently at the annual ACAAI meeting, in Seattle. Research presented at meetings is usually considered preliminary until published in a peer-reviewed medical journal.