Food Allergies

Overview

Allergic reactions to food occur when your immune system mistakes a food protein for something harmful. It creates a defensive reaction to fight it. The most common types of foods that trigger true allergic reactions are:

  • Peanuts
  • Tree nuts like walnuts, pecans, cashews, and almonds
  • Fish
  • Shellfish
  • Milk
  • Eggs
  • Soy products
  • Wheat
  • Sesame seeds

Most food reactions are food intolerances and not true allergies. Intolerances are non-immune reactions to foods. They can be caused by the inability to digest a food properly. We can help you learn to avoid foods that trigger your symptoms or treat a reaction if you have one. 

Symptoms

Symptoms of a food allergy usually occur quickly (30 to 60 minutes after eating or being exposed to the food). It may take only a small amount of the food to trigger a reaction. Your reaction can range from mild to severe.

Common symptoms of an allergic reaction are:

  • Itchy mouth and lips
  • Rash or hives
  • Itchy skin
  • Shortness of breath or wheezing
  • Chest pain
  • Gastrointestinal symptoms (nausea, vomiting, and diarrhea)
  • Throat swelling

Diagnosis

It is important to determine if you have a food allergy or intolerance. We will ask you about your medical history and examine you. This will help us decide if additional allergy tests are needed and how to interpret the test results. To better understand what is triggering symptoms, we may ask you to:

  • Keep a food diary. List everything you eat, and be specific. For example, don’t just list salad, but include the vegetables and salad dressing. 
  • Try an elimination diet. Stop eating all suspected foods to see if this improves your symptoms. We decide which foods to remove based on your medical history or your allergy test results. 

Treatments

Avoid problem foods. The most effective treatment is to avoid the foods that trigger symptoms. Here are some tips:

  • Learn to read food labels. Look for the ingredients that may cause your allergy. Avoid foods that were made in a facility that processes the foods you are allergic to. This is also stated on the label.
  • Prepare meals at home. Read food labels to avoid problem foods. Use fresh ingredients such as fruits and vegetables.  
  • Be careful in restaurants. Ask if the food ingredients you are allergic to are used in the kitchen. There could be cross-contamination with the food served to you.
  • Check ingredients in items other than food. Food ingredients that cause your allergies may be present in other items, such as toys or cosmetics.
  • Don't share utensils or kiss anyone who has eaten a problem food. Saliva may contain the food ingredient that causes your reactions. Be careful with kissing or sharing food utensils with someone else.

Additional Tests

Additional allergy tests may include:

  • Prick/puncture skin tests. We prick the skin of your arms or upper back with small amounts of the suspected food source.  If antibodies to the food are found, an allergic reaction occurs. This will cause a raised, red itchy area. This test takes about 20 minutes.
  • Blood tests.  Specific IgE tests use a sample of your blood to identify possible antibodies to foods. These tests may not be as sensitive as the prick/puncture skin tests. However, they may be safer for patients with severe symptoms.

Medication Treatments

Carry antihistamines with you at all times. Zyrtec (cetirizine) is a good antihistamine to treat mild allergic reactions. It is readily absorbed, and you can adjust the dose easily.

Carry and use epinephrine. We may prescribe an epinephrine autoinjector to treat severe reactions. Keep it with you at all times so that you can self-inject if you are accidentally exposed to a trigger food.


If you have an emergency medical condition, call 911 or go to the nearest hospital. An emergency medical condition is any of the following:
(1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.

This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.