ATLANTA – Systemic reactions against subcutaneous allergen immunotherapy have trended down overall in recent years, but there has been an uptick in reports of severe grade 4 reactions for reasons that are not yet clear, according to a review of 46.6 million injection office visits from 2008-2015.
The data come from annual surveys of members of the American Academy of Allergy, Asthma, and Immunology and of the American College of Allergy, Asthma, and Immunology, of whom 27%-51% responded each year.
Dr. Tolly Epstein
However, on surveys from 2013 to 2015, one grade 4 reaction – hypotension or respiratory failure – was reported for every 160,000 injection visits, up from one per million office visits in previous years. Two-thirds (152/252) of grade 3/4 systemic reactions (SRs) for 2014-2015 occurred in asthmatics. Among the three fatalities directly linked to allergy shots since 2008, all of them occurred in adults; two patients had asthma. The findings highlight the need for good asthma control before shots begin, with a forced expiratory volume of at least 70% in 1 second (J Allergy Clin Immunol. 2017 Feb;139[2]:AB377).
“Asthma remains a major risk factor for severe SRs... [It’s something] allergists need to be vigilant about,” said lead investigator Tolly Epstein, MD, an assistant professor of immunology at the University of Cincinnati.
It’s unclear if there has been a true increase in severe reactions, or simply better reporting of them since the reaction grading system started being used a few years ago. “I was surprised a little bit to see the uptick in severe systemic reactions, but I am not sure if it’s real yet,” Dr. Epstein said. She and her colleagues are collecting more data on the reports of severe reactions.
Dr. Epstein and her colleagues found in previous work that higher maintenance doses may increase the risk of SRs. The right balance between efficacy and safety is still being worked out, she said at the annual meeting of the American Academy of Allergy, Asthma, and Immunology.
The surveys started collecting data on infections from allergy shots in 2014, amid concerns about contaminants in compounded medications. The fact that none were reported probably isn’t a surprise to allergists, but it might be news to others who have raised concerns about the possibility, Dr. Epstein said.
Overall safety was good for sublingual allergen immunotherapy, first approved by the Food and Drug Administration in 2014. One of the grade 3 reactions was pharyngeal edema; the other involved throat tightening and lower respiratory symptoms.
One of the asthma patients who died was morbidly obese and under treatment for weed allergies during pollen season, and died from overwhelming laryngeal edema. The patient’s weight made IV access difficult. The other asthma patient had severe disease, and was on the maximum dose of fluticasone/salmeterol. He was on an accelerated buildup for dust mites, pollen, mold, and other allergies, and apparently died of asthma complications triggered by the shots. There were no known risk factors in the third death.
Mortalities are lower than they used to be in the past with allergy shots, Dr. Epstein said.
She said she had no relevant disclosures.