A new study has found that the vast majority of children treated for sudden allergic reactions may be spending far more time in hospital observation than necessary—adding to parental stress and burdening emergency departments unnecessarily.

Published in The Lancet: Child and Adolescent Health, the study analyzed data from over 5,600 emergency room visits across 31 hospitals in the U.S. and Canada and found that nearly 95% of children who received a single dose of epinephrine could be safely discharged within two hours. That number increased to 98% when children were observed for up to four hours.

Despite these findings, 17% of children were admitted for overnight observation, a precaution that researchers now say is rarely needed. “For most patients, we are probably observing them too long,” said Dr. Kenneth Michelson, a pediatric emergency medicine specialist at Ann & Robert H. Lurie Children’s Hospital of Chicago and one of the study’s authors.

“This might sound minor, but if you brought your toddler in for a scary allergic reaction, it's the difference between going home at 11 p.m. versus going home at 1 a.m. or 3 a.m.,” he added. “Our finding gives us more confidence that after a couple of hours, if symptoms are improving in specific ways, we can probably send the child home.”

The research focused on allergic emergencies—mostly triggered by common foods such as peanuts, eggs, milk, shellfish, sesame, gluten, or soy. Around 90% of the cases involved food allergies, with medications accounting for 6% and insect stings 3%.

One key concern during allergic emergencies is the risk of a biphasic reaction, where symptoms reappear after initially subsiding. However, the study found that only 5% of children required a second dose of epinephrine within two hours, and just 2% needed one after four hours. Importantly, most children who were admitted never required a second dose or advanced medical care.

“This means many families are enduring extended hospital stays with little medical benefit,” said Dr. Hugh Sampson, an allergist at the Icahn School of Medicine at Mount Sinai in New York City. “We’ve seen families delay going to the emergency department because they didn’t want to sit there for hours. This study supports quicker discharges, which may actually encourage more timely emergency visits.”

The implications go beyond individual families. Senior researcher Dr. David Schnadower, director of emergency medicine at Cincinnati Children’s Hospital, emphasized that prolonged, unnecessary stays can choke up already crowded emergency departments.

“Pediatric emergency departments can get overwhelmed, especially during winter infection season,” he said. “This study provides clinicians with enough evidence to feel confident that discharging patients showing no concerning symptoms in under two hours is safe in most cases.”

With food allergies and pediatric ER visits on the rise, the study calls for a shift in clinical practice to make allergy care safer, faster, and more efficient—without compromising patient outcomes.