Common Food Allergy Symptoms

Medically reviewed on May 17, 2023 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

• What Causes a Food Allergy?
• Gastrointestinal Discomfort
• Skin Rashes or Hives
• Difficulty Breathing
• Fainting or Loss of Consciousness
• Tingling Mouth or Throat
• Anaphylaxis
• Can You Prevent a Food Allergy?
• Assess Your Food Allergies and Sensitivities with Everlywell
• Related Content

Consuming certain foods such as nuts, milk, or wheat can trigger severe immune reactions in some people. To fend off the unwanted invader, the body releases antibodies that can bind to certain immune cells to release a variety of chemicals like histamine, a chemical that’s responsible for many food allergy symptoms. [1]

So, how long does a food allergy reaction last? Depending on the type of food allergy you have, symptoms of food allergies may arise in various parts of the body, including the gastrointestinal tract, the lungs, and the skin, among others. In some cases, reactions can be life-threatening. However, milder cases are more typical and usually resolve in a few hours. [2]

To better understand the relationship to certain foods and potential food intolerances, the six most common food allergy symptoms and how they may manifest in the body are outlined below.

What Causes a Food Allergy?

Food allergy symptoms will depend on the type of food allergy experienced. There are two types of food allergies: immunoglobulin E (IgE)-mediated food allergies and non-IgE-mediated food allergies.

Typically, food proteins will impact IgE levels. [3]

IgE refers to the antibody known as immunoglobulin E, which plays a key role in allergic reactions. It’s produced by the immune system and, upon ingesting an allergen, will disperse and bind itself to mast cells and basophils in the body. [4]

Mast cells are types of white blood cells found in the connective tissues of the skin, lungs, and intestines. [4] Basophils, on the other hand, are immune cells in the blood that release certain enzymes and chemicals during an allergic reaction. [5] As such, when IgE binds to these types of cells, chemicals, like histamine are expelled, and food allergy symptoms are triggered.

Symptoms develop rapidly and usually occur seconds or minutes after ingesting the allergen.

Typically, an IgE-mediated food allergy is confined to one part of the body. In some cases, it may affect multiple parts of the body, which can include: [3]

• Brain
• Circulatory system
• Eyes
• Heart
• Lungs
• Mouth
• Nose
• Skin
• Stomach
• Throat

IgE-mediated food allergies might also lead to anaphylaxis—a serious-to-life-threatening allergic reaction that can cause breathing difficulties, increased heartbeat, and loss of consciousness. [6]

Non-IgE-mediated food allergies, on the other hand, can lead to subacute or chronic inflammatory responses in the gut and gastrointestinal system. [7] These allergic symptoms usually take time to develop and may become chronic. [7]

These reactions are triggered by immune system components outside of IgE. Instead of IgE, T cells react to the allergen, or food protein, and trigger an immune response. That said, non-IgE-mediated food allergies are less understood than IgE-mediated food allergies and a lack of laboratory testing measures make it difficult to identify this type of reaction in people. [8]

Fortunately, researchers have identified that this type of food allergy is rarely life-threatening and will not cause anaphylaxis. [8]

All that said, some people can experience both IgE-mediated allergies and non-IgE-mediated allergies, particularly if they have a history of eczema. [9]

So, what are the most common signs of food allergies to look out for? Let’s explore.

1. Gastrointestinal Discomfort

As previously mentioned, non-IgE-mediated food allergies can impact the gastrointestinal tract and trigger a variety of food hypersensitivity syndromes, such as: [10]

• Food protein-induced enterocolitis syndrome (FPIES) – FPIES is a more severe form of non-mediated food allergies, and young infants are the most commonly affected. It’s believed that certain types of food allergens activate T cells in the intestinal lining, which can cause inflammation and a leaky gut. Individuals with FPIES may experience severe vomiting, diarrhea, and dehydration after eating. More severe symptoms can include changes in blood pressure, lethargy, and weight loss. [10]
• Allergic proctocolitis (AP) – AP is a more mild form of non-IgE-mediated food allergies and symptoms will often begin to present themselves in the first weeks of life. Symptoms include a combination of blood and mucous found in bowel movements, as well as diarrhea, abdominal pain, and gassiness. [10]
• Food protein-induced enteropathy (FPE) – FPE typically develops as a result of an intolerance to cow’s milk. However, soybean, wheat, and egg intolerances may also cause FPE. When cow’s milk or another protein allergen is consumed, the intestinal mucosa shrinks, which can cause diarrhea, dehydration, projectile vomiting, and, sometimes, shock. Some people may also experience abdominal distension or a lack of appetite. [10]
• Celiac disease – Celiac disease results from an intolerance to gluten, which can be found in grains like wheat, rye, and barley. In this case, dermatitis herpetiformis can occur, which causes chronic itchy or blistered skin. Gastrointestinal symptoms can include bloating, diarrhea, constipation, gassiness, abdominal pain, nausea, and vomiting. [10]

2. Skin Rashes or Hives

An IgE-mediated food allergy can trigger allergic reactions to the skin since mast cells are found in the vascularized tissues under the skin.4 Patients with these symptoms can experience: [2]

• Raised skin
• Itchy skin
• Red rashes
• Hives (urticaria)
• Eczema (scaly patches of skin)
• Swelling of the skin

Skin reactions to non-IgE-mediated food allergies are less common, but can still occur—such is the case with Celiac disease. That said, it’s important to note that skin reactions can also be caused by other factors as well, such as medications, insect bites, or exposures to irritants, so it’s important to seek medical attention to determine the cause of the skin reaction.

3. Difficulty Breathing

An inability to breathe is a common symptom of a severe allergic reaction, particularly in IgE-mediated food allergies. When a person with an IgE-mediated food allergy consumes an allergen, their immune system releases histamine, which can cause inflammation and narrowing of the airways in the lungs.

Respiratory-related symptoms may include: [11]

• Coughing
• Feeling suffocated
• Nasal congestion
• Rapid breathing
• Shortness of breath
• Tightness in the chest
• Wheezing

4. Fainting or Loss of Consciousness

Similarly, an IgE-mediated food allergy can trigger fainting or loss of consciousness, as a result of, or separate from anaphylaxis. More specifically, activation of the histamine receptors H1 in the brain cells, muscle cells, and blood vessels can cause hypotension, or low blood pressure. [1]

As a result, the brain, heart, and other parts of the body don’t receive enough blood, which can cause: [12]

• Blurred vision
• Dizziness
• Fainting
• Fatigue
• Nausea
• Trouble concentrating

Extremely low blood pressure can also lead to shock, which can lead to cold, clammy skin, rapid, shallow breathing, and a weak pulse. [12]

5. Tingling Mouth or Throat

Mild-to-moderate IgE-mediated food allergies can occur, specifically in the case of oral allergy syndrome (OAS). This type of allergic reaction is triggered when raw vegetables, fruits, or nuts come in contact with the mouth or throat.

The most common symptoms include itchiness or swelling of the: [13]

• Face
• Lips
• Mouth
• Throat
• Tongue

Some people may also experience hoarseness or trouble speaking. Researchers also found that seasonal allergies may impact certain food intolerances. For example, those who are allergic to airborne birch tree pollen may also be sensitive to pitted fruits or carrots. [13]

6. Anaphylaxis

In the most severe IgE-mediated food allergies, individuals can experience anaphylaxis. This occurs when IgE binds to immune cells and too many chemicals are released, which can put a person into shock. [14]

Symptoms can manifest quickly. [14] They can also last for up to 12 hours after the initial reaction. While early symptoms are mild—such as a runny nose or a skin rash—they can quickly develop into more life-threatening allergic reactions if left untreated.

These can include: [14]

• Abdominal pain
• Cardiac arrest
• Diarrhea
• Dizziness
• Fainting
• Feeling of doom
• Hives or swelling
• Hoarse voice
• Low blood pressure
• Nausea
• Rapid heartbeat
• Tightness of the throat
• Trouble breathing
• Vomiting

If you have a history of anaphylaxis or more severe IgE-mediated food allergies, it’s crucial to carry an epinephrine injectable pen with you. Epinephrine, or adrenaline, can help relax your muscles and reopen the airways. That said, if you or a loved one experience anaphylaxis, it’s also critical to visit a healthcare facility in which a healthcare professional can continue to monitor your condition.

Can You Prevent a Food Allergy?

The best way to prevent a food allergy reaction is to avoid foods that you’re sensitive to. Often, blood tests that monitor for antibody reactivity for IgE or Immunoglobulin G (IgG) can help guide you on what foods and proteins you should avoid.

However, researchers also believe that some factors may prevent the onset of certain food allergies. In a 2015 study, 640 children believed to be at high risk of a peanut allergy were enrolled into a clinical trial to assess possible prevention. [14]

Half of the children avoided all peanuts until they were five years old. The other group was given peanuts three times a week until they turned five. It was found that the children who were exposed to peanuts were 80% less likely to develop a peanut allergy. [14]

As such, it’s believed that regular exposure to certain allergens may decrease the likelihood of developing a food intolerance, or, at the very least, dampen the symptoms if an allergic reaction does occur.

See related: Are Food Allergies Genetic?

Assess Your Food Allergies and Sensitivities with Everlywell

Depending on the type of food allergy you have, symptoms will vary. Those with IgE-related food allergies might experience various effects throughout the body, from skin rashes and difficulty breathing, to oral tingling and anaphylaxis.

Conversely, those with non-IgE-mediated food allergies may only experience gastrointestinal issues, such as vomiting, bloating, and diarrhea. This type of food allergy can also develop into food hypersensitivity syndrome.

Fortunately, Everlywell offers two at-home blood tests to help assess your immune responses to certain proteins found in foods. The Food Sensitivity Test assesses IgG reactivity, while the Food Allergy Test assesses IgE reactivity to common food allergens, such as cow’s milk, peanuts, and wheat.

Take a proactive step toward your health and unlock peace of mind with Everlywell.

Related Content

Are Food Allergies Genetic?

How Long Does a Food Allergy Reaction Last?

Oral Allergy Syndrome Explained

References

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2. Food allergy. NHS Inform. URL. Accessed May 5, 2023.
3. Mast cell. National Cancer Institute. URL. Accessed May 5, 2023.
4. Basophil. National Cancer Institute. URL. Accessed May 5, 2023.
5. IgE-mediated food allergies. Children’s Hospital of Philadelphia. URL. Accessed May 5, 2023.
6. Zhang S, Sicherer S, Berin M, Agyemang A. Pathophysiology of non-ige-mediated food allergy. ImmunoTargets and Therapy. URL.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8721028/. Published December 29, 2021. Accessed May 5, 2023.
7. Allergy and immunology. The Royal Children’s Hospital Melbourne. URL. Published November 11, 2016. Accessed May 5, 2023.
8. Connors L, O’Keefe A, Rosenfield L, Kim H. Non-IgE-mediated food hypersensitivity. BMC. URL. Published September 12, 2018. Accessed May 5, 2023.
9. Mehta Y, Fulmali DG. Relationship Between Atopic Dermatitis and Food Allergy in Children. Cureus. doi:https://doi.org/10.7759/cureus.33160. URL. Published online December 31, 2022.
10. Food allergy. Mayo Clinic. URL. Accessed May 5, 2023.
11. Low blood pressure (hypotension). Mayo Clinic. URL. Accessed May 5, 2023.
12. Oral allergy syndrome (OAS). American College of Allergy, Asthma and Immunology. URL. Published September 28, 2020. Accessed May 5, 2023.
13. Anaphylaxis. American College of Allergy, Asthma and Immunology. URL. Published January 29, 2018. Accessed May 5, 2023.
14. Identifying causes of food allergy & assessing strategies for prevention. National Institute of Allergy and Infectious Diseases. URL. Published October 26, 2018. Accessed May 5, 2023.