Dr. Mersad Alimoradi 03 Nov 2021

Did you know that almost every 3 minutes, someone is sent to the emergency room because of food allergies?

About 32 million people have food allergies in the United States alone. That means 1 out of 10 adults and 1 in 13 children.

Food allergy symptoms can range from mild to severe. However, these differ in individual cases and are often unpredictable. Common mild symptoms include an itchy throat and diarrhea, among others.

However, severe symptoms often need immediate emergency medical attention to prevent the risk of complications. Severe food allergies can quickly become life-threatening, leading to anaphylaxis or other fatal complications if left untreated.

Keep reading to find out which worrying signs you need to look out for and when you need to head to the emergency room (ER).

What Is A Food Allergy?

Normally, the role of your immune system is to fight off infections and diseases. In people with allergies, however, the immune response is triggered by harmless substances in the environment called “allergens”. These can be found in food, dust, animal hair, or anywhere.

A food allergy is the reaction of your body’s immune system to ingestible allergens.

Whenever you eat allergy-causing food, the immune cells in your digestive tract are triggered and release histamine. Histamine is a powerful irritant that triggers allergic symptoms, like swollen airways or digestive problems.

Worldwide, about 6% to 8% of children under the age of 3 have some kind of food allergy. In adults, around 3% of men and women are affected. However, these vary between individual persons, and the severity can change from time to time.

So, just because your initial allergic reaction caused mild symptoms, that doesn’t mean it can’t be severe next time.

These 8 types of food cause 90% of allergic reactions:

  • Milk and dairy
  • Eggs
  • Tree Nuts
  • Peanuts
  • Shellfish
  • Wheat
  • Soy
  • Fish

These are only the most common causes of food allergy, however, there are many other foods that can trigger an allergic reaction.

Common Mild Symptoms Of Food Allergies

Allergy symptoms can take anywhere between a few minutes to 2 hours to develop after eating. Symptoms can affect your skin, gastrointestinal tract, respiratory system, and cardiovascular system.

For some, an allergic reaction causes only mild symptoms that may only affect one part of the body, usually your skin. For others, the reaction might be more extensive.

Here are a few mild symptoms associated with the most common food allergies:

  • Itchy rash
  • Itchy mouth and throat
  • Swollen lips
  • Wheezing or nasal congestion
  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal pain
  • Lightheadedness
  • Dizziness

In many people, symptoms of food allergy stop here and don’t develop into something worse. However, in some, an allergic reaction might become life threatening. As long as the symptoms remain mild and are not increasing slowly in intensity, then you might be able to wait out the allergic reaction at home.

If you have any severe food allergy symptoms, signs of anaphylaxis (see below), or worsening symptoms, then you should go to the ER immediately.

When To Visit The ER: 5 Worrying Symptoms Of Food Allergies

Sometimes, a food allergy can trigger a severe reaction called Anaphylaxis. Symptoms of anaphylaxis can start mild but can quickly turn worse.

If you notice these warning signs in yourself or someone else, you need to go to the emergency room or call for emergency treatment immediately.

1. Breathing difficulty

As an immune response, your body releases hormones that can cause your airways to narrow, resulting in difficulty breathing. If left untreated, it can lead to a loss of consciousness. Visit the ER as soon as you notice difficulty breathing or start to hear wheezing.

2. Difficulty swallowing

The flood of hormones also triggers swelling of your airways and throat as an immune response. As a result, eating and swallowing become challenging. You might feel a lump in your throat when trying to swallow. This needs immediate medical care since it can lead to breathing issues or a choking hazard.

3. Rapid pulse

Anaphylaxis can cause an increase in your heart rate and, sometimes, arrhythmia. Arrhythmia is a problem with the rate or rhythm of your heartbeat. Your heart may beat too slow, too fast, or with an irregular rhythm.

4. Dizziness or fainting

When you have a food allergy, your body starts an immune response against the allergens in the food. Your cells produce massive amounts of an antibody known as immunoglobulin E (IgE) to neutralize the allergens. As a result, you may feel lightheaded, dizzy, or nauseous. If this persists, you may end up fainting.

5. Low blood pressure

Your immune system releases chemical substances, like histamine, that cause your blood vessels to expand, resulting in a severe drop in blood pressure. This is what we call hypotension. Severe hypotension may eventually lead to a loss of consciousness.

6. Worsening Symptoms

If the symptoms keep on developing as the time passes, you need to seek medical care. Even if it’s just a rash that keeps spreading, or mild swelling in the lips that are becoming worse - this might be a sign that you’re heading toward anaphylaxis.

Food allergies should not be taken lightly. Anaphylaxis has a rapid onset and is considered a medical emergency. If you, or anyone you know, experience severe or worsening signs of food allergies, then go to the nearest emergency room for immediate medical care.

Complications of Food Allergies

Your symptoms and the severity of your condition can be unpredictable. Mild symptoms can quickly worsen and become fatal if not treated right away.

One complication of food allergies is anaphylactic shock. When your blood pressure drops in a severe allergic reaction, your body goes into shock, and your organs and cells may not get enough oxygen.

If treatment is not delivered on time, vital organs may fail, and there is a risk of going into cardiac arrest or even death.

It’s impossible to know what type of allergy symptoms you will experience. Don’t wait until your symptoms worsen and become fatal before seeking emergency care.


Prevention is the best treatment for food allergies. However, should you ingest food that causes a reaction, there are different treatments depending on the severity of your allergy.

Medical treatment for food allergies usually includes:


Antihistamines treat mild to moderate allergic reactions.

Food allergens increase the production of histamine to fight off the allergen. Histamine is responsible for the mild allergy symptoms you may experience. The antihistamine works by targeting and blocking the action of histamine.

Many over-the-counter antihistamines are readily available for you to keep on hand at all times. You can take these antihistamines after you eat allergy-causing food to relieve symptoms like itching or hives.


Adrenaline is an emergency medication that treats severe allergic reactions like anaphylaxis.

Your body’s natural response to anaphylaxis is to release adrenaline, also known as epinephrine. Injected adrenaline boosts your natural response and helps relieve symptoms. Adrenaline reduces swelling, opens your airways to ease up your breathing, and maintains your normal blood pressure.

You can carry around an emergency adrenaline auto-injector, like the EpiPen, and inject it into your outer mid-thigh when you feel severe symptoms of food allergy.


What are the most common food allergies?

The most common causes of food allergies include soybeans, peanuts, milk, wheat, eggs, fish, shellfish, and tree nuts.

What are the most common food allergens?

Allergen information must be provided on prepackaged and non-prepackaged food or drink. Common food allergens you may find on food products include milk, peanuts, celery, cereals containing gluten, crustaceans, mollusks (mussels and oysters), eggs, fish, lupin, mustard, soybeans, sesame, sulfur dioxide, and sulfites.

How do I know what food I am allergic to?

You may approach an allergy specialist for skin tests and blood tests to determine which food you are allergic to. In a skin test, they prick your skin with a small amount of allergen. A small red bump means that you are allergic to that specific food.

How do I know if I am getting an allergic reaction?

An allergic reaction may manifest as difficulty breathing and swallowing, nausea, itchiness in your mouth or throat, coughing, abdominal pain, vomiting, or hives. If you are experiencing any of these symptoms, seek medical treatment right away.

How long does a food allergy reaction last?

A food allergic reaction can last for several hours after the first signs and symptoms appear. Mild symptoms may take up to 1-2 days to disappear. Severe symptoms will need immediate medical attention and can take a few days to go away.

Can food allergies go away?

Many children with food allergies can outgrow them with little management. Few adults develop a tolerance; however, there is no cure for food allergies. The best way to prevent food allergies is to avoid taking food that you’re allergic to.

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About the Author:
Dr. Mersad is a medical doctor, author, and editor based in Germany. He's managed to publish several research papers early in his career. He is passionate about spreading medical knowledge. Thus, he spends a big portion of his time writing educational articles for everyone to learn.


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