Food Allergy Overview
If you have a food allergy, your immune system overreacts to a particular protein found in that food. Symptoms can occur when coming in contact with just a tiny amount of the food.
Many food allergies are first diagnosed in young children, though they may also appear in older children and adults.
Eight foods are responsible for the majority of allergic reactions :
- Cow’s milk
- Tree nuts
Many people who think they are allergic to a food may actually be intolerant to it. Some of the symptoms of food intolerance and food allergy are similar, but the differences between the two are very important. If you are allergic to a food, this allergen triggers a response in the immune system. Food allergy reactions can be life-threatening, so people with this type of allergy must be very careful to avoid their food triggers.
Being allergic to a food may also result in being allergic to a similar protein found in something else. For example, if you are allergic to ragweed, you may also develop reactions to bananas or melons. This is known as cross-reactivity. Cross-reactivity happens when the immune system thinks one protein is closely related to another. When foods are involved it is called oral allergy syndrome (OAS).
There is no cure for food allergies, but many children outgrow their food allergy.
Food Allergy Symptoms & Diagnosis
Allergic reactions to food normally occur within minutes of eating the trigger food, though they can sometimes appear a few hours later. Symptoms of a food allergy include :
- Hives or red, itchy skin
- Stuffy or itchy nose, sneezing or itchy, teary eyes
- Vomiting, stomach cramps or diarrhea
- Angioedema or swelling
In some cases, food allergies can cause a severe reaction called anaphylaxis. Signs of this reaction include :
- Hoarseness, throat tightness or a lump in the throat
- Wheezing, chest tightness or trouble breathing
- Tingling in the hands, feet, lips or scalp
- If you experience any of these symptoms, call 911 immediately.
Proper diagnosis of food allergies is extremely important. Studies have shown that many suspected food allergies are actually caused by other conditions such as a food intolerance. Skin tests and blood tests are often ordered. A food challenge under the care of your allergist / immunologist may also be needed to confirm an allergy.