It's important to differentiate between a food allergy and a food intolerance. A food allergy involves the immune system, while a food intolerance typically involves the digestive system and doesn't trigger an immune response. Consulting with a healthcare professional and undergoing proper testing can help diagnose food allergies accurately.
Food allergy symptoms can vary widely from person to person and can range from mild to severe. They typically occur shortly after consuming or coming into contact with the allergen and can affect different parts of the body. Common symptoms of a food allergy include:
- Digestive problems: Nausea, vomiting, diarrhoea, abdominal pain, cramps.
- Skin reactions: Itching, hives (red, raised welts on the skin), eczema (itchy, inflamed skin), redness, swelling.
- Respiratory issues: Sneezing, runny or stuffy nose, coughing, wheezing, shortness of breath, difficulty breathing, chest tightness.
- Swelling: Swelling of the lips, tongue, throat, face, or other parts of the body.
- Cardiovascular symptoms: Rapid or weak pulse, light-headedness, dizziness, fainting.
- Anaphylaxis: A severe, potentially life-threatening reaction involving multiple systems of the body, characterised by a drop in blood pressure, loss of consciousness, and difficulty breathing. Anaphylaxis requires immediate medical attention.
Symptoms of a food allergy can occur within minutes to a couple of hours after consuming the allergen. In severe cases, anaphylaxis can happen rapidly, within minutes, and requires immediate treatment with adrenaline and emergency medical care.
It’s important to note that the severity and type of symptoms can differ among individuals, and some may experience only mild symptoms while others might have more severe reactions. If someone suspects they have a food allergy based on their symptoms, it’s crucial to speak to a healthcare professional for accurate diagnosis, testing, and guidance on managing food allergies.
Types of food allergies
Food allergies are divided into 3 types, depending on symptoms and when they occur:
IgE-mediated food allergy is the most common type, triggered by the immune system producing an antibody called immunoglobulin E (IgE). Upon subsequent exposure to the same food allergen, the allergen binds to the IgE antibodies on the mast cells, triggering these cells to release various chemical substances, including histamine and other inflammatory mediators. This release of chemicals leads to the symptoms associated with an allergic reaction.
Symptoms of an IgE-mediated food allergy occur a few seconds or minutes after eating. Symptoms can range from mild to severe and may include skin reactions (such as itching, hives, or eczema), digestive issues (like vomiting, diarrhoea, or abdominal pain), respiratory symptoms (such as coughing, wheezing, or difficulty breathing), swelling of the lips, tongue, throat, or face, and in severe cases, anaphylaxis, a potentially life-threatening reaction affecting multiple systems of the body.
Non-IgE-mediated food allergies refer to allergic reactions that occur without involving Immunoglobulin E (IgE) antibodies. Unlike IgE-mediated allergies, these reactions involve different components of the immune system and have a delayed onset.
Mixed IgE and non-IgE-mediated food allergies: Some individuals may experience a combination of both IgE-mediated and non-IgE-mediated responses to certain foods. This type of allergy can present with both immediate (IgE-mediated) symptoms, such as hives or swelling, as well as delayed (non-IgE-mediated) symptoms, such as gastrointestinal disturbances or skin issues.
It’s essential for individuals with food allergies to be aware of their specific allergens, read food labels carefully, avoid cross-contamination, and have an emergency action plan in case of accidental exposure. Consulting with a healthcare professional and undergoing allergy testing can help determine specific food allergies and appropriate management strategies.
Diagnosing a food allergy is essential for preventing reactions, managing symptoms, improving quality of life, avoiding unnecessary dietary restrictions, and ensuring proper support and guidance for individuals living with food allergies.
Diagnosing a food allergy is crucial for several reasons:
- Accurate identification of triggers
- Prevention of severe reactions
- Avoidance of unnecessary dietary restrictions
- Finding the right support and guidance.
If you are looking for help and advice or information, you can call Allergy UK’s Helpline on 01322 619898, they can support you through your food allergy journey and advise on your nearest NHS allergy clinic or consultant.
Types of food allergy testing
There are several types of allergy tests used to diagnose different types of allergies, including food allergies, environmental allergies (like pollen or pet allergies), medication allergies, and others. Some common allergy tests include:
- Skin Prick Test (SPT): This test involves placing a small amount of allergen extract on the skin (usually on the forearm) and then pricking or scratching the skin to allow the allergen to enter. If a person is allergic to the substance, a raised, red, itchy bump (called a wheal) will appear within about 15-20 minutes.
- Blood Tests: Blood tests measure the levels of specific IgE antibodies to various allergens in the blood. These tests can identify specific allergens that may trigger allergic reactions.
- Oral Food Challenge: This involves consuming small amounts of a suspected food allergen under medical supervision to confirm or rule out a food allergy. It’s considered the most accurate way to diagnose a food allergy but is performed in a controlled setting due to the risk of severe reactions.
- Elimination Diet: This isn’t a test in the traditional sense but a method used to identify food triggers by eliminating suspected allergens from the diet and then gradually reintroducing them while monitoring for reactions.
The choice of allergy test often depends on the type of allergy suspected, the individual’s medical history, and the allergens being tested for. These tests should always be conducted and interpreted by a healthcare professional, such as an allergist or immunologist.