At least 1.6 percent of Americans, and possibly as many as 5.1 percent, have experienced anaphylaxis, the potentially life-threatening allergic reaction, according to the first extensive study of the condition’s prevalence.
Dr. Robert Wood, the lead author on the study, published in the Journal of Allergy and Clinical Immunology, says that anaphylaxis used to be considered rare but with this study’s results, it’s clear that these serious reactions are now common. “If you were to go to a gathering of 100 people, you would have at least three to four who have a history of anaphylaxis and that’s pretty remarkable,” he said in an inteview with Allergic Living.
Wood, the chief of pediatric allergy and immunology at Johns Hopkins Children’s Center, says of the 1.6 percent estimate: “it’s almost certainly higher than that; we just did not feel comfortable on being specific on how much higher it is.”
The study, called Anaphylaxis in America: The Prevalence and Characteristics of Anaphylaxis in the United States, was developed by the Asthma and Allergy Foundation of America (AAFA). It is based on two surveys: one of 1,000 adults in the general population and the other of 1,059 patients with diagnosed allergies to foods, medication, insect stings and latex.
The prevalence statistics were drawn from public survey, and the 1.6 percent statistic was based on the strictest criteria for “very likely anaphylaxis”. The respondents, all adults, had to have experienced a reaction that involved: at least two organ systems including either cardiovascular and/or respiratory symptoms; a trip to the hospital; and a feeling that life was in danger.
The 5.1 percent group was considered have had “probable anaphylaxis” – a reaction that involved two or more organ systems with cardiovascular or respiratory symptoms.
The findings on anaphylaxis symptoms were similar for both the public and patient surveys, with respiratory distress, skin reactions and swelling of the eyes, lips and tongue as the most frequently cited.
While the AAFA study finds anaphylaxis a fairly common occurrence, it also highlights a disturbing trend of patients either failing to own an auto-injector, or failing to use one when needed. Sixty percent of those who reported two or more anaphylactic reactions did not currently own an auto-injector.
“We think there are patients who leave the emergency room with a prescription in hand, who decide not to fill it,” says Wood. “And we think there are at least as large number who have actually had a prescription at some point but have decided not to maintain one over time.”
He hopes that through drawing attention to the magnitude of anaphylaxis as a health issue, “this gives a big impetus to a larger public health initiative that would focus on education both for the consumer and the health-care provider.”
See also: AAFA’s media release on the study.