6 Anaphylaxis Myths and Facts

From the WebMD Archives

You could save someone's life if you know how to recognize and handle the dangerous allergic reaction called anaphylaxis. Are you ready? Check to make sure you understand the symptoms, causes, and treatment.

Myth No. 1: Anaphylaxis is always obvious.

Fact: You might picture it as a dramatic "I can't breathe" problem, but it doesn't always look like that to other people.

Breathing trouble is often a sign, but not always. You may also have itchy skin or hives, trouble swallowing, digestive problems, chest pains, dizziness or fainting, or simply feel like something really bad is happening.

Anaphylaxis affects more than one organ, says David Stukus, MD, assistant professor of pediatrics at Nationwide Children's Hospital in Columbus, Ohio. "So somebody could be vomiting and having trouble breathing, or vomiting with hives, but any combination of these things should make you act promptly."

Symptoms can be mild at first, "but the scary thing is it can progress very rapidly," Stukus says. "Some people may not show any outward symptoms. They may just feel that sense of doom and have very mild hives, then all of a sudden their throat swells shut."

Myth No. 2: It happens right away.

Fact: Anaphylaxis usually happens 5 to 30 minutes after you come in contact with one of your allergy triggers -- usually an insect sting, a food (like nuts or shellfish), a medication, or a material like latex. But in rare cases, symptoms don't start until more than an hour later.

After you get treated, anaphylaxis symptoms can come back. That's why it's so important to go to the hospital, where you can be watched for several hours after a serious allergic reaction, even if you think it's under control, Stukus says.

Myth No. 3: If your previous reaction was mild, you don't have to worry.

Fact: If you have asthma, eczema, allergies, or a family history of serious allergic reactions, you're more likely to have anaphylaxis. Even if your allergies have never been life-threatening before, that doesn't mean you're in the clear.

"Often people feel comforted if their prior reactions were mild, and they don't realize their next reaction could be very different and very bad," Stukus says.


If you have a history of allergies, talk with your doctor about whether you're at risk for anaphylaxis and what you should do to prepare.

Myth No. 4: You can treat it with over-the-counter drugs.

Fact: Anaphylaxis must be treated right away with epinephrine, a hormone that raises heart rate and opens airways. You use an auto-injector to get it into your body. You press this device against your upper thigh and inject the medicine into the muscle.

Even if there's no proof that the symptoms are directly related to an allergic reaction, don't take that risk. Use the injector anyway, because it won't harm you if turns out the issue isn't linked to an allergy.

Auto-injectors are available by prescription only. If you're at risk for anaphylaxis, always carry two with you. If you don't have one and you or someone with you has anaphylaxis, call 911 right away.

"Many people will treat with antihistamines or steroids first before giving epinephrine, and that is completely inappropriate," Stukus says. The longer anaphylaxis goes without proper treatment, the riskier it gets.

Remember, you still need to go to the hospital.

Myth No. 5: It's hard to inject epinephrine.

Fact: It's safe and easy to do, Stukus says. People often worry about side effects, but there are few. Or they may be squeamish about using a needle.

"I had a situation recently where a mother knew her son was having anaphylaxis but she could not bring herself to inject him," Stukus says. "She was paralyzed by fear of doing something wrong, but in reality, doing nothing is the worst thing you can do."

If you have an auto-injector, talk with your doctor about the right way to use it. "I strongly recommend anyone given a prescription have the opportunity to practice with a training device [which has no medicine in it], so they can learn what it actually feels like," Stukus says.

Myth No. 6: It's easy to pinpoint the cause.

Fact: Often, anaphylaxis triggers are obvious, like if you're stung by a bee and swell up right away. But sometimes, you may not get a reaction immediately, or you may be in contact with several new foods, medicines, or materials all at once.


In up to half of all cases of repeated anaphylaxis, a cause is never found. Doctors call this "idiopathic" anaphylaxis.

Even if you think you know what the trigger was, it's still important to visit an allergist and have tests done to find out for sure. "If you base it on history alone, you may give yourself an incorrect diagnosis, which can affect your ability to avoid or treat anaphylaxis in the future," Stukus says.

When you see your allergist after an anaphylaxis episode, you'll also learn more about what puts you at risk, find out what to do in an emergency, and get advice to manage your allergy and stay safe.

WebMD Feature Reviewed by Jennifer Robinson, MD on October 18, 2015



Kids with Food Allergies: "Anaphylaxis: Severe Allergic Reactions."

National Institute of Allergy and Infectious Diseases: "Anaphylaxis."

American Academy of Allergy, Asthma, and Immunology: "Anaphylaxis."

David Stukus, MD, spokesman, American College of Allergy, Asthma, and Immunology.

American Academy of Allergy, Asthma, and Immunology: "Food Allergies."

The Asthma Center: "Anaphylaxis."

Medscape: "Epinephrine."

National Institute of Allergy and Infectious Diseases: "You could be a part of an investigational treatment for idiopathic anaphylaxis."

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