FRIDAY, July 10, 2015 (HealthDay News) -- About 15 percent of children who have a severe allergic reaction (anaphylaxis) can have a second one within a few hours, a new study shows.
"The key message here for parents, caregivers and first responders is to administer epinephrine at the first sign of a severe allergic reaction to prevent anaphylaxis from worsening," Dr. James Sublett, president of the American College of Allergy, Asthma, and Immunology, said in a college news release.
"Anaphylaxis symptoms occur suddenly and can progress quickly. Always have a second dose with you and, when in doubt, administer it, too. Anaphylaxis can be fatal if left untreated," he added.
Early symptoms of a severe allergic reaction may be mild, such as a runny nose, skin rash or "strange feeling." But these symptoms can quickly progress to more serious problems, including difficulty breathing, hives or swelling, throat tightness, nausea, abdominal pain and even cardiac arrest, the researchers said.
The study team looked at the medical records of almost 500 children seen in an emergency department for severe allergic reactions to determine whether the children had a second, follow-up reaction.
These delayed reactions occur when the initial symptoms of an allergic reaction subside but then return hours later. This second reaction occurs even though the children haven't been exposed again to the allergen that caused the first reaction, explained the authors of the study published recently in the journal Annals of Allergy, Asthma and Immunology.
About one in seven kids had a second reaction, the researchers found.
"We found that 75 percent of the secondary reactions occurred within six hours of the first," lead author Dr. Waleed Alqurashi, from the University of Ottawa in Canada, said in the news release.
"A more severe first reaction was associated with a stronger possibility of a second reaction. Children aged 6 to 9, 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," Alqurashi said.
At least half of the second allergic reactions were considered serious and had to be treated with epinephrine.
The U.S. National Institute of Allergy and Infectious Diseases has more about anaphylaxis.
SOURCE: American College of Allergy, Asthma and Immunology, news release, July 7, 2015