People with food and other allergies have a new way to treat severe reactions

The hormone epinephrine is the go-to therapy for anaphylaxis, a potentially life-threatening reaction that can happen after exposure to a food, a drug or insect venom for those who are allergic. The immune system’s exaggerated response during anaphylaxis leads to low blood pressure and difficulty breathing, among other symptoms. From 2004 to 2016, there were about two cases of anaphylaxis per 1,000 people per year nationally, with 25 percent of anaphylaxis reactions occurring in children 16 years and younger. It’s rare that anaphylaxis leads to death, but there isn’t a way to predict when it might.

The method of delivery for epinephrine has long been a needle: a shot or a device called an auto-injector. For people at risk of anaphylaxis, the medical recommendation is to use epinephrine at the first signs of the reaction. Symptoms tend to resolve quickly with one dose. A research review estimated that about 1 in 10 anaphylaxis reactions are treated with more than one dose. Auto-injectors come as two-packs so people at risk can carry two doses.

But studies have found that some people don’t use epinephrine during a severe allergic reaction. Some fear needles and some parents worry about hurting their kids when administering a dose. Having a non-needle option that’s easy to use “is a game-changer,” says allergist immunologist Theresa Bingemann of the University of Rochester Medical Center in New York.

Science News talked to two experts about what happens during an allergic reaction, how epinephrine applies the brakes and why neffy might help fill a problematic gap in health care.

What’s happening in the body during anaphylaxis and how does epinephrine halt the reaction?

Anaphylaxis can happen within minutes of exposure to an allergen. Certain immune cells in the body release the chemical histamine and other compounds that lead to, among other harms, plummeting blood pressure, constricted airways and leaky vessels. People can develop hives or swelling, have trouble breathing, wheeze, cough, become nauseous, vomit or pass out. Patients have described anaphylaxis as “an impending sense of doom,” says pediatric allergist Carla Davis of Baylor College of Medicine and Texas Children’s Hospital in Houston. “They feel like something really bad is happening.”

Epinephrine is also called adrenaline, known as the “fight or flight” hormone. It counteracts anaphylaxis by constricting blood vessels to increase blood pressure and by relaxing the airways to restore easy breathing, among other actions. Medical guidelines recommend using epinephrine at the start of anaphylaxis symptoms, especially if signs occur in two different parts of the body, such as the skin and the lungs. The earlier people treat, the sooner they feel better, Bingemann says. “We usually tell people: When in doubt, treat.”

Will the nasal spray work if a person is having trouble breathing?

The epinephrine in the nasal spray isn’t meant to be inhaled. The medicine is absorbed in the nasal mucosa. It’s the same as with the naloxone spray, Narcan. That medicine is given to people experiencing an opioid overdose, which also causes difficulty with breathing.

Each neffy spray contains one dose. The instructions call for inserting the nozzle in a nostril until the fingers can touch the nose and then pressing the plunger. If needed, a second dose would go in the same nostril.

How was the nasal spray tested?

ARS Pharmaceuticals conducted several clinical trials to compare the absorption and action of epinephrine via the nasal spray, auto-injector and shot. The concentrations of epinephrine in the blood reached comparable levels in a similar amount of time after delivery from the three methods, the research found. The increases in blood pressure and heart rate produced by the three methods were also similar. The results held up in another study that compared the self-administration of neffy with an injection of epinephrine by a healthcare provider.

In a study of neffy in children weighing 30 kilograms or more, the concentration of epinephrine in the blood matched what was seen in adults, according to the FDA.

What kind of impact could the availability of epinephrine nasal spray have on anaphylaxis treatment?

“It’s a big deal,” Davis says. In her experience, people can be very hesitant to treat anaphylaxis with epinephrine. Some people are afraid of needles or feel anxious about administering epinephrine. Some people aren’t sure how to use the auto-injectors. Cost has also been an issue, with the list price for a two-pack of a widely used auto-injector reaching around $600 in 2016.

Many episodes of anaphylaxis happen in the community, outside of medical settings. A 2018 study in Annals of Allergy, Asthma & Immunology found that more than 50 percent of adults and 30 percent of children reported at least one severe allergic reaction in which an epinephrine auto-injector would have helped but wasn’t used. “It’s a huge gap in care,” Davis says.

Multiple episodes of untreated anaphylaxis can affect people’s quality of life, Davis says. “What I see is anxiety in children, in adults, staying away from social situations.”

Epinephrine “only works if you have it and you use it,” Bingemann says, and the best device is the one that works best for an individual. The nasal spray offers a choice that could “give people more confidence in their ability to treat a reaction because they don’t have to poke themselves with a needle,” she says. If the new method helps more people use epinephrine promptly, “that would be great and I’m hoping that’s what we’ll ultimately see.”