CANNABIS ALLERGY IN A YOUNG CHILD WITH SEVERE ASTHMA EXPOSED TO SECONDHAND MARIJUANA SMOKE

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 (figure 1). 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. Basophil Activation Test Results Figure 1. Basophil activation (measured by percent of CD203c expression) to cannabis in the patient and a control.