Oral Immunotherapy Linked to Anaphylaxis in Teens with Asthma

New research suggests that oral immunotherapy may trigger anaphylaxis in an unusually high percentage of asthmatic teenagers with food allergies and lackluster discipline.

The study, which just appeared in Annals of Allergy, Asthma and Immunology, followed 130 children who underwent such treatment in Barcelona hospital.

All of the children, whose ages ranged from 5 to 18, received a two-day induction at the hospital before going home with supplies and instructions for daily treatment. Most of the children suffered no severe reactions, but anaphylaxis was more common among the 45 patients (including 13 adolescents) who had moderate to severe asthma.

The oral immunotherapy triggered anaphylaxis in 22 of the patients. All such reactions required at least one shot of epinephrine, but 3 of them — all in teenage boys with serious asthma — intensified enough to be classified as life threatening.

The victim in one of those cases had actually completed his 17 months of oral immunotherapy, but he had failed to follow treatment protocols exactly. He also had poorly controlled asthma thanks to his tendency to neglect his salbutamol and his decision to start smoking.

That patient experienced immediate dizziness and dyspnea when he ingested 6 grams of cow’s milk. His blood pressure then plummeted and he fell unconscious before suffering respiratory arrest and erythema. Medical personnel had to intubate him and give him 2 shots of epinephrine during a 28-hour period of invasive ventilation at the ICU.

The second patient to develop life-threatening anaphylaxis had skipped the previous 3 days of oral immunotherapy before his reaction because he disliked milk. His parents had decided to secure his compliance by substituting custard for milk, but they miscalculated the portion and gave him 3.5 grams of milk protein rather than the 3 grams his therapy advocated.

That boy soon began vomiting and then experienced urticaria, severe bronchoconstriction and hypotension with decreased hypoxia. He was treated with 3 doses of epinephrine, volume expansion, inotropes, intravenous salbutamol, steroids, and 48 hours of invasive ventilation.

The third patient to develop life-threatening anaphylaxis fell ill shortly after increasing his dose of egg protein to 1.8 grams in the fourth week of his immunotherapy. He experienced severe bronchoconstriction, hypotension with hypoxemia and dizziness followed by urticaria. His treatment included 3 shots of epinephrine, nebulized salbutamol, intravenous hydroxyzine, intravenous saline, and 8 hours of noninvasive ventilation.

That boy had been taking the correct amount of egg protein, but he later admitted that he had noticed dyspnea 10 minutes before his reaction worsened yet failed to notify anyone and failed to treat himself. He also struggled to keep his asthma under control.

The study authors noted that the limited size of the study population with allergies — particularly teenagers with allergies — limited the strength of their findings, but they still concluded that allergies were associated with a significant increase in the likelihood that oral immunotherapy would trigger anaphylaxis in children.

Moreover, they wrote, the fact that 3 of just 13 asthmatic adolescents in the study developed life-threatening anaphylaxis, and that all of the cases seemed to stem from their failure to follow medical directives, suggests that doctors should regard them as a high-risk group for oral immunotherapy.