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the food allergy app—

from Allergy Force

  • Writer's pictureRed Sneakers for Oakley

Anaphylaxis and Biphasic Allergic Reactions: What You Should Know

A mother holds and comforts a young boy in her arms by Jordan Whitt on Unsplash

Managing an Allergic Reaction

Do you know the symptoms of anaphylaxis and when to give epinephrine?

It’s not uncommon for people to second guess whether they’re experiencing anaphylaxis — and many times, they will wait until symptoms get worse.* But waiting can be very dangerous.

People have this idea that anaphylaxis means your throat is closing and you’re turning blue…and anything less is just a mild reaction.

Well, that’s simply not the case.

The table below summarizes Severe Symptoms vs. Mild Symptoms of anaphylaxis. The information is sourced from the FARE (downloadable) Food Allergy & Anaphylaxis Emergency Care Plan that has been reviewed and approved by FARE’s Medical Advisory Board.**

Chart that lists the Severe and Mild Symptoms of anaphylaxis. Data sourced from FARE's publicly available Food Allergy & Anaphylaxis Emergency Care Plan

It can take more than an hour for symptoms to manifest.

It’s important to follow the Emergency Care Plan you prepare with your medical provider. Make sure your Emergency Care Plan includes monitoring for a secondary reaction (i.e., a biphasic reaction—explained below.) Review the plan periodically so you know exactly what to do in a food allergy emergency, and then follow your plan to the letter during an allergic reaction.

If you do not have your own Emergency Care Plan, you can use these steps from FARE’s Food Allergy & Anaphylaxis Emergency Care Plan as a guide:**

For any severe symptoms, inject epinephrine immediately, then:

  1. Call 911. Tell the emergency dispatcher the person is experiencing anaphylaxis and may need epinephrine when emergency responders arrive.

  2. Consider giving additional medications after epinephrine (e.g., an inhaler if wheezing, antihistamine.)

  3. Lay the person flat, raise their legs and keep them warm. If breathing is difficult or they are vomiting, let them sit up or lie on their side.

  4. If symptoms do not improve, or symptoms return, another dose of epinephrine can be given 5 minutes or more after the last dose.

  5. Alert emergency contacts.

  6. Transport the patient to ER, even if symptoms resolve, and monitor there in case symptoms return.

For mild symptoms from more than one body system, give epinephrine.

For mild symptoms from a single body system (e.g., skin, GI), do the following:

  1. Give antihistamines if ordered by a doctor.

  2. Stay with the person; alert emergency contacts.

  3. Watch closely for changes. If symptoms worsen, give epinephrine.

But, it doesn’t end here...

Biphasic Reactions

If your child has experienced an anaphylactic reaction, it's crucial to stay with them even if they seem stable after the first reaction.


Because anaphylaxis doesn't always resolve with the first reaction.

Even after initial treatment and stabilization, a second wave of symptoms can occur between 1 and 72 hours after initial symptoms have resolved, despite no further exposure to the trigger.

This is called a biphasic reaction (or anaphylaxis part two).

Data from the Anaphylaxis Registry (data from 10 European countries plus Brazil) on 8,736 patients with monophasic anaphylaxis and 435 patients with biphasic anaphylaxis were analyzed. The analysis found that for secondary onset reactions, 60.5% occurred within 12 hours of the initial reaction and 84.4% occurred within 24 hours. The rate of secondary onset reactions among patients, however, was only 4.7% of the data set analyzed.

Biphasic reactions are like aftershocks following an earthquake.

A secondary reaction can catch you off guard, and that’s why constant vigilance is key.

  1. Don't let your guard down too soon: Stay by your child’s side and keep a watchful eye on them.

  2. Know the signs: Know the symptoms of anaphylaxis so you can act swiftly if they re-emerge.

  3. Keep epinephrine within immediate reach: You should have a minimum of two epinephrine auto-injectors on hand, know how to use them, and be resolved to use them.

And when in doubt — EPI FIRST, EPI FAST! — because epinephrine saves lives.

Until a cure is found for food allergies, all we can do is educate ourselves as well as the people around us — schools, workplaces, camps, churches, daycare centers, and even medical professionals — on how serious food allergies are. If you don’t know where to start, we can help you plan a Red Sneaker Day at your school, work or community center to help raise awareness. We will provide all the materials you’ll need. Learn more about this and if you have questions, please email us at

Black and white illustration of high top sneakers enclosed  by the outline of a heart. Canva creation by Allergy Force.

We are not medical professionals and the best practices and data provided in this article are sourced from food allergy advocacy and medical organizations. For medical advice specific to your situation please consult your medical provider.

Helpful Resources


To learn more about why people hesitate to administer epinephrine, and how families have overcome hesitation, check out these articles on epinephrine hesitation from Allergy Force and Allergic Living Magazine.


The information in this article is based on FARE’s downloadable Emergency Care Plan (also available in Spanish.) The plan was revised by FARE’s Education Working Group, a multidisciplinary group of food allergy experts including support group leaders, two members of FARE’s Medical Advisory Board, experienced parents of children with food allergies, an adult with food allergies, a dietitian, psychologist and a school nurse. The plan was approved by FARE’s Medical Advisory Board.

Put on your red sneakers

In memory of Oakley

In support of food allergy awareness


In November 2016, the Debbs Family tragically lost their 11-year-old son, Oakley, to a fatal anaphylactic reaction resulting from a nut allergy. Shortly after Oakley’s death, the family decided to publicly share Oakley’s story to help raise awareness about the dangers of food allergies. They saw a need for awareness and founded the non-profit organization Red Sneakers for Oakley in memory of their son. Oakley wore red sneakers in the multiple sports he played so it was only natural that the family looked to Oakley’s favorite shoes as a powerful symbol to represent the severity of food allergies. Please support @redsneakersforoakley.

Credits: Content courtesy of Red Sneakers for Oakley; Image courtesy Jordan Whitt on Unsplash

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