Food Allergy
Definition and Overview
A food allergy is a medical condition in which exposure to certain foods triggers a harmful immune response. This immune response is caused by the body's immune system mistakenly identifying certain proteins found in food as harmful. The proteins that trigger the response are called allergens. The severity of food allergies can range from mild to severe, including the potentially life-threatening condition known as anaphylaxis.
Causes and Pathophysiology
Food allergies occur when the body's immune system mistakenly identifies a protein in food as harmful and produces antibodies in response. This is known as an immune response. The antibodies produced by the body are called Immunoglobulin E (IgE) antibodies. These antibodies are designed to fight off the perceived threat, which in this case is the food protein (allergen). When the individual eats the food again, the IgE antibodies trigger an immune response, releasing chemicals like histamine that cause allergy symptoms.
Common Food Allergens
The most common food allergens are proteins found in eight foods: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans. These eight foods account for about 90% of all food allergies. Other less common food allergens include corn, meat, seeds (like sesame), spices, and certain fruits and vegetables.
Symptoms
Symptoms of food allergies can range from mild to severe and can affect various parts of the body at the same time. Some common symptoms include: hives, itching or eczema; swelling of the lips, face, tongue, and throat or other parts of the body; wheezing, nasal congestion or trouble breathing; abdominal pain, diarrhea, nausea or vomiting; dizziness, lightheadedness or fainting.
Diagnosis
Diagnosis of food allergies can be complex, as symptoms can mimic other medical conditions. A healthcare provider will typically use a combination of methods to diagnose a food allergy, including a detailed medical history, a physical examination, and diagnostic tests such as skin prick tests, blood tests, oral food challenges, and trial elimination diets.
Treatment and Management
There is currently no cure for food allergies. The main treatment for food allergies is avoidance of the allergenic food. Individuals with food allergies must read food labels carefully to avoid consuming the allergenic food. In cases of accidental ingestion, medications like antihistamines and corticosteroids can help to control symptoms. Individuals with severe food allergies may need to carry an epinephrine autoinjector (EpiPen) with them at all times.
Prevention
While there is no surefire way to prevent food allergies, some research suggests that early introduction of allergenic foods may help to reduce the risk of developing food allergies. It is important to consult with a healthcare provider before introducing allergenic foods to infants.