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Food Allergy Symptoms

What is a food allergy?

A food allergy occurs when an individual’s immune system overreacts to a particular food substance. The immune system is primarily responsible for defending the human body against germs. However, when a person has a food allergy, their body mistakenly believes that food is dangerous and proliferates signals to attack an otherwise harmless substance. Most food allergies stem from the Big 8: dairy, eggs, fish, shellfish, peanuts, tree nuts, wheat, and soy. However, it is possible to experience an allergic reaction to any other foods as well.


Food allergies are an improper and unpleasant immune system response in which the body produces IgE antibodies against the offending food. These responses can often be dangerous. Repeated exposure to the food increases cell-mediated reactions, leading to allergic symptoms.

How do I know if I have a food allergy?

The symptoms of food allergies will typically occur a few minutes up to 2 hours after consuming a particular food. Symptoms rarely manifest after 4 to 6 hours. The most common symptoms of food allergies include:

  • Vomiting, diarrhea, and/or abdominal pain
  • Hives, eczema, and/or bodily swelling
  • Itching or swelling of the lips, tongue, or mouth
  • Itching or tightening of the throat
  • Difficulty breathing and/or wheezing
  • Dizziness or feeling faint due to lowered blood pressure

What foods cause allergic reactions?

Although any food can cause an allergic reaction, most food allergies occur with exposure to the top eight food allergens:

  • Peanuts
  • Tree nuts (such as walnuts, almonds, Brazil nuts, cashews, macadamia nuts, pecans, pine nuts, and hazelnuts)
  • Eggs
  • Soy
  • Wheat or other grains
  • Shellfish
  • Fish
  • Cow’s milk

Peanuts, tree nuts, fish, and shellfish typically cause the most severe reactions. Children's food allergies commonly include eggs, milk, peanuts, wheat, soy, and tree nuts. Although most children may “outgrow” their allergies, allergic reactions to peanuts, tree nuts, fish, and shellfish tend to be lifelong and continue into adulthood.

How is a food allergy diagnosed?

Food allergies are very tricky to diagnose. Your allergist will consider a variety of factors including your symptoms, family history of food and environmental allergies, a comprehensive physical examination, skin test, blood test, elimination diet and an oral food challenge before making a diagnosis.

Which medications interfere with food allergy testing?

People should discontinue taking antihistamines and antidepressants before undergoing allergy skin testing, as these medications may interfere with the food allergy test results. It is essential to consult your healthcare provider regarding any questions you may have. Prior to ceasing any of these, ensure that you have consulted your healthcare provider.

What can I do to treat my food allergy?

Although there are no definitive treatment options to completely cure a food allergy, there are some ways you can manage it. Before recommending a plan, your physician will guide you through a process to diagnose food allergies. At Frontier Allergy Asthma and Immunology, an allergy specialist will obtain vital information that will help you understand what food substances may be causing issues for you. Detailed review of symptom and family history, skin prick tests, and blood tests will provide your physician with vital information about what food(s) could potentially cause an allergic reaction. Your physician may recommend an elimination diet, which involves removing certain foods from your diet and slowly re-incorporating them one by one and monitoring your symptoms. You also have the option of undergoing a physician-supervised oral food challenge. Your physician will measure out exact amounts of a potential allergen to ingest in increments over a set amount of time. Doing so can help determine if a food you may have once been allergic to in the past may be added back into your diet. Avoiding the food substances that causes allergic reactions is the best way to prevent one, but it is always possible that cross-contamination can occur. Your allergist will provide a detailed plan that you can follow in case of an emergency and a safety medicine, epinephrine (EpiPen), for you to carry at all times.

Next steps

If you are interested in further discussion about your specific needs, Dr. Reshamwala is happy to see you and answer any questions you may have. Please call (512) 535-2655 or email to schedule an appointment today! Book an appointment

Written by: Dr. Neha Reshamwala
NPI number: 1780874578
Page last reviewed: 03/20/21

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