ARLINGTON HEIGHTS, Ill., July 7 (UPI) -- The more severe an allergic reaction a child has, the more likely that child will have a second reaction within hours of the first, even without being exposed to the triggering allergen again, according to a new study.
Researchers said they identified clinical triggers that should be used to identify patients who would benefit from longer preventative stays in the emergency room after an initial reaction.
"We found that 75 percent of the secondary reactions occurred within six hours of the first," said Waleed Alqurashi, M.D., an assistant professor at the University of Ottawa, in a press release. "A more severe first reaction was associated with a stronger possibility of a second reaction. Children aged six to nine, children who needed more than one dose of epinephrine and children who do not get immediate epinephrine treatment were among the most likely to develop secondary reactions."
Researchers reviewed the records of 484 children who visited the emergency room for anaphylaxis. Of those, 14.7 percent developed a biphasic, or secondary, reaction -- 69 percent of which involved a respiratory or cardiovascular issue, with 49 percent receiving epinephrine for the second reaction.
Based on records of the 71 children who had secondary reactions, researchers determined five factors which, independent of each other, can help predict if further observation in the ER is necessary after an initial reaction has been treated: a delay of getting to the ER more than 90 minutes after the first reaction started; wide pulse pressure at triage; more than one dose of epinephrine used to treat the initial reaction; respiratory distress treated with inhaled salbutamol; and children between the age of 6 and 9.
"It's clear that children with severe initial reactions would benefit from a prolonged period of observation in the Emergency Department," continued Alqurashi. "On the flip side, knowing what to look for helps to better utilize resources so that children with mild allergic reaction, who do not match any of the identified predictors can go home faster."
The early symptoms of anaphylaxis can include a runny nose, a skin rash or a "strange feeling," which can quickly lead to more serious problems, including trouble breathing, hives, swelling, tightness of the throat, nausea, abdominal pain or cardiac arrest.
The study is published in Annals of Allergy, Asthma, and Immunology.