How do food allergies affect the immune system?

Food allergies occur when the immune system mistakenly identifies a food protein as harmful, triggering an inappropriate immune response. This reaction, mediated by immunoglobulin E (IgE) antibodies, can cause a range of symptoms from mild skin irritation to life-threatening anaphylaxis. While there’s no cure, managing food allergies involves strict avoidance of the offending food and having medications like epinephrine on hand for emergencies.

How Do Food Allergies Affect the Immune System?

When a person with a food allergy is first exposed to a particular food, a process called sensitization occurs. During this phase, the immune system recognizes a protein in the food as an allergen and produces IgE antibodies specific to that allergen. These IgE antibodies attach to mast cells and basophils, which are immune cells found throughout the body.

The next time the person eats that food, the allergen binds to the IgE antibodies on the surface of mast cells and basophils. This triggers the release of various inflammatory molecules, such as histamine, into the surrounding tissues. These chemicals cause the symptoms associated with food allergies, which can affect various organ systems.

What Are the Common Symptoms of Food Allergies?

Symptoms of food allergies can vary widely depending on the individual and the amount of allergen consumed. Some common symptoms include:

• Gastrointestinal issues: Vomiting, diarrhea, abdominal pain
• Skin reactions: Hives, eczema, itching
• Respiratory problems: Wheezing, difficulty breathing, nasal congestion
• Oral allergy syndrome: Itchy and swollen lips, tongue, and throat
• Anaphylaxis: A severe, potentially life-threatening reaction involving multiple organ systems

What is Anaphylaxis?

Anaphylaxis is the most severe type of allergic reaction and can be fatal. It occurs when the release of inflammatory chemicals causes a sudden drop in blood pressure, difficulty breathing, and loss of consciousness. Anaphylaxis requires immediate treatment with an epinephrine injection to reverse the symptoms and stabilize the person until they can receive emergency medical care. People with known food allergies and a risk of anaphylaxis should always carry an epinephrine auto-injector (like an EpiPen) and know how to use it.

How Are Food Allergies Diagnosed?

Diagnosing food allergies can be challenging, as symptoms can be caused by various other conditions. Several methods are used to identify food allergies, including:

• Skin prick test: Small amounts of common allergens are scratched onto the skin. A red, itchy bump indicates a possible allergy.
• Blood test: Measures the level of IgE antibodies specific to certain allergens in the blood.
• Elimination diet: Suspect foods are removed from the diet and then reintroduced one at a time to see if symptoms return.
• Oral food challenge: The person eats increasing amounts of the suspected food under medical supervision to monitor for a reaction.

How Are Food Allergies Treated and Managed?

The primary way to manage food allergies is strict avoidance of the allergenic food. This involves carefully reading food labels, asking about ingredients when eating out, and educating family members, caregivers, and school staff about the allergy.

For accidental exposures, medications like antihistamines can help relieve mild symptoms. However, for severe reactions like anaphylaxis, epinephrine is the only effective treatment. People with food allergies should work with an allergist to develop an emergency action plan and learn how to use an epinephrine auto-injector.

Are There Any Emerging Treatments for Food Allergies?

While there is currently no cure for food allergies, researchers are exploring several potential treatments, including:

• Oral immunotherapy (OIT): Gradually increasing doses of the allergenic food are given over time to desensitize the person.
• Sublingual immunotherapy (SLIT): Small doses of the allergen are placed under the tongue to build tolerance.
• Allergy shots: Injections of the allergen are given to desensitize the person.

These treatments are not yet widely available and should only be undertaken under the guidance of an experienced allergist.

Food allergies are a significant health concern affecting millions of people worldwide. By understanding how food allergies affect the immune system and taking appropriate steps to manage them, individuals with food allergies can live healthier and safer lives.

Would you like to learn more about specific food allergens and how to avoid them?