When you learn that you or your child have an allergy, life changes. You have to take the steps necessary to avoid exposure to that allergen, which can be extremely difficult if it is a common food item, and you have to learn to live with the threat of anaphylaxis, a life-threatening allergic reaction.
“That anxiety can be paralyzing,” says UNC Health allergist and immunologist Sofija D. Volertas, MD. “A parent of a child with a food allergy has to worry about exposure several times a day—every meal, every snack.”
Dr. Volertas says it’s important to understand the risk of anaphylaxis, but that your anxiety can lessen when you learn to recognize and treat it.
“Anaphylaxis can be unpredictable and needs to be treated seriously, but it’s rare for it to be fatal,” she says. “It’s manageable. We absolutely know how to treat this so that you’ll feel better in a few minutes and can go about your day.”
Here’s what you need to know.
How Anaphylaxis Happens
Anaphylaxis is most commonly caused by allergies to food, medications, venom from bug bites or stings, and latex. If you have an allergy to something, your immune system has decided it’s a threat and mounts a response to it. This happens via an interaction of mast cells, the main allergy cell, and immunoglobin E (IgE), an antibody produced by the immune system that remains on guard for the allergen.
“When that mast cell gets triggered by an allergen, IgE says, ‘release everything inside this cell,’” Dr. Volertas says. “The cell immediately releases histamine and other chemicals that cause inflammatory reactions over a span of eight to 12 hours.”
While those chemicals can have effects that last that long, Dr. Volertas says that symptoms appear within a few minutes up to a few hours after exposure.
“Typically, you don’t eat something the night before and have something happen the next day,” she says.
The response of one mast cell causes other cells to respond, producing more and more histamine. That release of histamine causes most of the symptoms associated with allergic reactions and anaphylaxis.
Symptoms of Anaphylaxis
The release of histamine causes a range of symptoms, affecting four main body systems:
- Skin: Symptoms include itching, flushing, redness, hives, welts and swelling of the lips or tongue.
- Gastrointestinal: Symptoms include nausea, stomach cramps, diarrhea or vomiting.
- Respiratory: The person may feel that they’re having an asthma attack, sense their throat is closing or feel spasms in their lungs. They may have difficulty breathing or start to wheeze and cough. Without treatment, the person could stop breathing.
- Cardiovascular: Blood pressure will drop, affecting the heart rate. The person may feel lightheaded or dizzy and can pass out. Without treatment, the heart can stop.
If you have one symptom, you might be having a mild allergic reaction, but if you have any two symptoms, you’re experiencing anaphylaxis, and without treatment, symptoms could continue to develop and progress until the body goes into shock from a lack of oxygen and blood pumping from the heart.
“A lot of people think that anaphylaxis is only when you’re having difficulty breathing, but it’s when there are two systems involved,” Dr. Volertas says. “It could be hives, or it could be vomiting, or it could be difficulty breathing, but it doesn’t have to include all of these. It’s not isolated to any particular symptom.”
A person may experience different symptoms every time they have anaphylaxis, and the severity and progression of those symptoms can vary as well.
“Severity can change every time you’re exposed,” Dr. Volertas says. “If you’re under increased stress, if you didn’t get enough sleep, if you’ve been exercising, if you’ve had alcohol, if it’s your first meal of the day—all of these are factors that can contribute to the severity of the reaction.”
That means that even if you’ve historically had mild reactions to allergens, you’re still at risk for anaphylaxis.
“An allergy test can’t tell the severity of reaction you’ll have, only whether you’re allergic to something,” Dr. Volertas says. “If you’re allergic, any time you have an exposure, there is a potential for it to be life-threatening.”
Still, Dr. Volertas says there’s no need to wait for those life-threatening symptoms of difficulty breathing or changes in blood pressure to show up; instead, treatment can begin as soon as you start to experience symptoms.
Treatment for Anaphylaxis
There is only one treatment for anaphylaxis: epinephrine, or adrenaline. Epinephrine counteracts the effects of histamine, preventing more symptoms from developing, while also working to treat the existing symptoms. It is typically injected into the thigh muscle with a needle (the most common brand name is EpiPen).
“If two systems of the body are involved, use epinephrine immediately,” Dr. Volertas says. “If you think you need epinephrine, use it. The earlier you use, the more likely you are to prevent a severe reaction.”
Once epinephrine is administered, symptoms tend to improve almost immediately; if they don’t improve within five minutes, you can administer a second dose. EpiPens come as a two-pack, and Dr. Volertas says a common mistake is splitting those two doses and putting them in separate places. Instead, keep both with you in case of an exposure.
Don’t Delay in Using Epinephrine
Unfortunately, many people are reluctant to use injectable epinephrine.
“The biggest reason is probably fear of using the needle,” Dr. Volertas says. “It also used to be drilled into patients that after using epinephrine, they had to go to the emergency room for monitoring, and that caused hesitancy. People might think that if they’re not having trouble breathing, they don’t need it; that if it’s not bad enough, they can wait it out.”
There are new developments that might increase the likelihood that people will use epinephrine when symptoms start. In 2024, the FDA approved the use of a nasal spray containing epinephrine for people weighing more than 66 pounds.
And in recent years, allergists have eased their recommendation about going to the emergency department after administration of epinephrine, with the American College of Allergy, Asthma & Immunology (ACAAI) and the American Academy of Allergy, Asthma & Immunology (AAAAI) changing their guidelines in 2023.
“If you know what you are allergic to, only use one dose of epinephrine, and your symptoms get better, that’s it—you don’t have to go to the emergency room,” Dr. Volertas says.
If you use two doses of epinephrine, or if your symptoms don’t improve after two doses, then you should go to the emergency department, where they will administer more epinephrine while trying to provide symptom relief with other medications if necessary.
While mild symptoms can eventually resolve on their own, it’s impossible to predict when they might become more severe, which is why doctors urge people to use epinephrine once two symptoms are identified.
“If you just have hives, for example, you can try an antihistamine like cetirizine (Zyrtec) to treat a skin symptom to see if that gets better, but it won’t prevent anaphylaxis,” Dr. Volertas says. “Even if the skin gets better and you have a second symptom, then you need to use epinephrine. There’s not any major harm in using it even if you don’t need it, and you can decrease the severity of your reaction and feel better quickly.”
Epinephrine can cause side effects including dizziness or shakiness as the adrenaline restores your blood pressure, but these tend to be milder than the symptoms of anaphylaxis.
While constantly carrying epinephrine may seem stressful or annoying, its effectiveness should be reassuring.
“Fatal anaphylaxis is incredibly rare, because we have this tool that will stop the symptoms right away in epinephrine,” Dr. Volertas says. “It’s important to have two doses with you, and the earlier you can use it, the better.”
Concerned about allergies? Talk to your doctor. If you need a doctor, find one near you.