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Food Allergies

According to the U.S. Food and Drug Administration (FDA), food allergies occur when the body's immune system reacts to specific proteins in the food. 

Allergic reactions can vary in severity from mild symptoms that cause hives to severe, life-threatening symptoms, like anaphylaxis.

Cause of Food Allergies

Food allergies occur when your immune system reacts to what you eat. Your immune system has two components that are involved in this process.

Immunoglobulin E (IgE) – They are antibodies in your blood produced by your immune system. If you have an allergy, your immune system overreacts to an allergen by producing IgE.

Mast cells – These are immune cells present in the connective tissues throughout your body. They are found in your nose, throat, lungs, skin, and digestive tract. Mast cells are rich in chemicals like histamine and heparin. Histamine makes you sneeze, tear up, or itch to help your body eliminate an allergy trigger or allergen.

When you have a food allergy, your immune system mistakenly identifies a specific food or a substance in food as something harmful. It then releases a lot of antibodies (IgE) to fight off the allergen. The IgE attaches to the surface of the mast cells throughout the body.

The next time you eat the same food, the antibodies sense it and trigger the mast cells to release excess histamine. 

Your body takes these steps to protect you from allergens. But its overreaction causes bothersome allergy symptoms.

Timeline for Allergic Reactions

The speed at which allergy signs and symptoms appear depends on the digestive process. You may feel itching in your mouth, followed by vomiting, diarrhea, or a stomachache.

Food allergens in your blood can cause a drop in blood pressure. And as they reach your skin, they can trigger hives or eczema. In the lungs, they may cause wheezing.

These reactions may take a few minutes to a couple of hours to manifest.

Common Food Allergy Triggers

Most food allergies are triggered by specific proteins in:

  • Shellfish, such as shrimp, lobster, and crab
  • Peanuts
  • Tree nuts, such as walnuts and pecans
  • Fish
  • Chicken eggs
  • Cow's milk
  • Wheat
  • Soy

If you feel you may be allergic to certain types of foods, pay close attention to what you are consuming to identify your triggers.

Symptoms of Food Allergies

Symptoms of a food allergy are usually evident in your body soon after consuming the allergen. 

You will likely develop an allergic reaction within a few minutes to 2 hours after eating the food item.

The most common symptoms of a food allergy include:

  • Tingling or itching in the mouth
  • Hives, itching, or eczema
  • Swelling of the lips, face, tongue, throat, or other parts of the body
  • Wheezing, nasal congestion, or trouble breathing
  • Abdominal pain, diarrhea, nausea, or vomiting
  • Dizziness, lightheadedness, or fainting


For some people, a food allergy can trigger a severe allergic reaction called anaphylaxis. 

Anaphylactic shock is a rare but severe allergic reaction that can be deadly if you don't treat it immediately. Symptoms of Anaphylactic shock include :

  • Swelling of your mouth
  • Tight feeling in your throat and difficulty breathing
  • Severe drop in blood pressure
  • Vomiting
  • Dizziness or loss of consciousness
  • Rapid heartbeat

Epinephrine injection is needed immediately to treat Anaphylaxis, and you should call 911 for emergency medical help. Emergency treatment is critical for anaphylaxis. Untreated, anaphylaxis can cause coma or even death.

Types of Food Allergies

Pollen-Food allergy

Also known as oral allergy syndrome, pollen-food allergy syndrome occurs if you are sensitive to various types of pollen, such as:

  • Birch pollen – People with severe birch pollen allergy may react to apple peels.

  • Ragweed pollen - Eating melons, especially cantaloupe, during ragweed season can make your mouth itch.

  • Grasses – For people with hay fever, certain fresh fruits and vegetables or nuts and spices can trigger an allergic reaction that causes the mouth to tingle or itch.

In severe cases, the reaction can result in swelling of the throat or even anaphylaxis.

Exercise-Induced Food Allergy

This distinct type of food allergy manifests when you perform physical exercise after consuming a food allergen. It occurs only when a sensitized individual consumes the allergen before heavy physical activity (within a particular time frame).

In this case, the food(s) alone or the exercise alone will not trigger the allergic reaction. It is the combination of the two that induces a response. 

Severe cases may even involve hives or anaphylaxis. Not eating for a couple of hours before exercising and avoiding certain foods can help prevent this problem.

Precautions for Food Allergies

Unfortunately, food allergies are not curable. However, some people may outgrow the food allergies they may have developed during childhood. 

In any case, early recognition and management are critical measures for dealing with food allergies.

FDA regulations mandate that all companies list the ingredients of any packaged foods and beverages they produce. This information is beneficial for those with food allergies and other food hypersensitivities.

If you know you have a food allergy, read the food labels of packaged food carefully. The best way to prevent an allergic reaction is to know what foods to avoid.

Food Allergy Management in Portland

If you need advice on managing your food allergies, call West Hills Allergy & Asthma Associates for a consultation with Dr. Rene Anderson-Cowell. You can call us at (503) 297-4779 or request an appointment online.

9701 SW Barnes Road
Suite 130
Portland, Oregon 97225


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