An estimated 20 million people in the US have food allergies. Source: AAFA

What is a Food Allergy?

food allergy, also known as food hypersensitivity, occurs when the body’s immune system incorrectly identifies a harmless food protein as a threat and reacts against it. This reaction can manifest quickly or within a few hours after ingestion, leading to symptoms ranging from mild discomfort to severe, life-threatening conditions. Food allergies are notably prevalent among children, with peanuts being one of the most common triggers. Recent research suggests that food allergies are on the rise, possibly due to changes in dietary habits and environmental exposures. Understanding and managing food allergies is crucial for the well-being of those affected.

Food Allergy Symptoms

All food allergy reaction symptoms should be taken seriously, and an allergist should be consulted when suspected. However, some reactions can be uncomfortable, and others can be life-threatening.

Mild Food Allergy Symptoms

  • Hives, Itchy Skin, or Skin Reaction
  • Coughing
  • Headache
  • Stomach Ache
  • Diarrhea
  • Eczema

Severe Food Allergy Symptoms

In some cases, food allergies can result in symptoms that are much more severe, even fatal. Rapid onset of these can be signs of anaphylaxis and require immediate medical treatment. Patients who develop any of the following symptoms should seek medical help immediately.

  • Tightening in the throat, hoarseness
  • Tightening in the chest or trouble breathing
  • Drop in blood pressure leading to rapid dizziness or fainting
  • Vomiting
  • Difficulty breathing
  • Swollen eyes or lips
woman making a peanut butter sandwich

Delayed Allergic Reactions to Food

It’s crucial to understand that an allergic reaction may not always occur immediately after consuming food. This is especially important to recognize in children who may not be aware that they are experiencing a reaction. Delayed allergic responses can be deceptive, leading individuals to underestimate the severity of their condition.

Experts stress the importance of being vigilant for any signs of an allergic reaction, no matter how mild, and recommend using an epinephrine auto-injector at the first sign of trouble. Given the unpredictability of how rapidly a mild reaction can escalate into a life-threatening situation, this precautionary measure could be lifesaving, especially when dealing with children who might not recognize or communicate their symptoms effectively.

woman having an allergic response to shellfish

When to See a Doctor

When should you see a doctor vs when to go to the Emergency department? Unclear reactions require professional insight—if there is a repetitive pattern of mild symptoms, schedule an appointment with an allergist.

Call 911 or go to the nearest emergency department in cases of severe reactions or anaphylaxis.

Risk Factors of Food Allergies

Risk factors can vary from person to person and allergy to allergy. Below are the general rule of thumb for the increased risk of having a food allergy or developing another one:

Family history of food allergies

We know that genetic factors can play a role and increase the chance of the individual having food allergies.

Existing food allergy

This can be a good sign to do a full allergy testing panel to learn if you have more allergies.

Environmental allergy

Additional exposure to environmental allergens can contribute to a food allergy.

Childhood eczema

Children with moderate to severe eczema have a greater risk of food allergies.

Composition with common food allergens including egg, milk, soya, peanuts, hazelnut, fish, seafood and wheat flour

Most Common Food Allergy Triggers

There are some common foods that trigger the majority of food allergies. Common food allergy triggers include:

  • Cow’s milk
  • Eggs
  • Peanuts
  • Tree nuts (almonds, Brazil nuts, walnuts, hazelnuts, macadamia nuts, pistachios, pecans, and cashews)
  • Fish (salmon, tuna, anchovy, cod, bass, flounder, haddock)
  • Shellfish (shrimp, crab, lobster, crawfish, clam, oyster, scallop)
  • Soy and sesame
  • Wheat


Cow's Milk and Eggs


Tree Nuts



Rare Triggers

Food Allergy Cross-reactivity

Food Allergy vs. Food Intolerance VS. Food Sensitivity  

Some who think they have a food allergy may instead have what is known as a food intolerance.

While these two conditions share many symptoms, it is important to understand that a food allergy triggers an immune response and can, therefore, be fatal in some cases. A food intolerance causes digestive issues and discomfort, typically, and are less serious. This is the main and most important difference between food allergy and food intolerance.

When one has a food intolerance, you may be able to consume small amounts of the food and only experience symptoms when you consume large amounts.

Food intolerance can be caused by several different triggers, including:

  • Sensitivity to additives
  • Lacking a necessary digestive enzyme
  • IBS

Some patients may have an aversion to certain foods due to stress or psychological factors, as well.

Whats the Difference Between Food INtolerance and Food Sensitivty?

Gluten is probably the best-known trigger of food sensitivities, but the best tool for identifying food sensitivities is careful observation and experimentation. A physician or nutritionist can provide guidance for undertaking an elimination diet, help you understand limitations, and avoid possible pitfalls.

According to Harvard Health, food sensitivity is when certain foods create an immune reaction that generates various symptoms. These symptoms are not life-threatening but may include:

  • Joint Pain
  • Stomach Pain
  • Fatique
  • Rashes
  • Brain fog
Man with food poisoning holding stomach

Other Conditions That Cause Food Allergy-Like Symptoms

It’s important to recognize that not all adverse reactions to food are due to allergies. Several conditions can mimic the symptoms of food allergies, making diagnosis a careful process.

For instance, the absence of an enzyme required for digesting certain foods can lead to symptoms similar to those of food allergies. Food poisoning, often resulting from contaminated food, can also mirror allergic reactions, as can sensitivity to food additives present in many processed foods.

Additionally, Celiac disease, an autoimmune disorder triggered by gluten, can cause reactions that closely resemble those of food allergies. Understanding these conditions is crucial for accurate diagnosis and treatment.

How Food Allergies Are Diagnosed & Tested

Consulting with an allergist is crucial to diagnosing a food allergy. The allergist may recommend undergoing specific diagnostic tests, such as allergy skin or blood tests, to identify the allergens with high precision. Additionally, be prepared for likely questions about your medical history, symptoms, and dietary habits to accurately determine the cause of your allergic reactions. This comprehensive approach ensures a correct diagnosis, guiding you to improved health and wellness.

Your allergist may order one or several tests to get a complete picture of your condition(s); standard diagnostics are:

Food Allergy Treatments

Currently, there’s no cure for food allergies, but several treatments can help manage the symptoms. The recommended treatment varies depending on the severity and type of allergy, so it’s essential to consult with a healthcare professional to determine the best approach for each individual case.



Benadryl, along with other medications like Zyrtec and Claritin, can be effective in managing the symptoms of food allergies. These antihistamines work by counteracting the body’s histamine response to allergens, helping to alleviate reactions such as itching, swelling, and hives. When taken as directed, they can provide significant relief from food allergy symptoms, making them a valuable part of managing allergic reactions.



Allergy immunotherapy makes you less sensitive to the things that trigger allergies and allergic asthma. Ongoing research is exploring immunotherapy as a treatment option for food allergies. Still, it’s an ideal choice for patients with severe allergies who are unable to avoid exposure to an allergen.


Epinephrine Auto-Injector

When faced with a food allergy that can cause an anaphylactic response, it is essential to carry an Epinephrine auto-injector with you. Quick administration increases the chance of survival during anaphylactic episodes. To learn how to use one, visit our step-by-step blog.

Prevention & Management of Food Allergies

There is no known cure for food allergies; however, patients can take steps to manage their condition. In some cases, treatment options may be available to help lower the risk of a reaction. Talk with your allergist today about the right plan for your condition.



Prevention & Avoidance

The American Academy of Pediatrics and allergists encourage introducing the 8 most common food allergens into a baby’s diet before 11 months of age. This can help prevent the development of allergies to those foods.

Those who have known allergies should avoid any and all exposure to food allergy triggers. Several different habits form in everyday life.


Mild Reactions

Reactions can vary but the most common are skin reactions, oral itching, mild abdominal pain. Any food allergy reaction or intervention should be pursued by a consultation with a medical professional.


Severe Reactions

Any person who has a severe food allergy should create and maintain an allergy action plan in partnership with their doctor. This includes carrying and knowing how to use an epinephrine autoinjector.

Frequently Asked Questions

What Is the Most Common Food Allergy?

What Does a Food Allergy Rash Look Like?

How To Get Tested for Food Allergies

Can Food Allergies Cause Fever?

Can You Develop Food Allergies Later in Life?