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).
Food allergy can strike children and adults alike. While many children outgrow a food allergy, it is also possible for adults to develop allergies to particular foods.
Food Protein-Induced Enterocolitis Syndrome (FPIES), sometimes referred to as a delayed food allergy, is a severe condition causing vomiting and diarrhea. In some cases, symptoms can progress to dehydration and shock brought on by low blood pressure and poor blood circulation.
Much like other food allergies, FPIES allergic reactions are triggered by ingesting a food allergen. Although any food can be a trigger, the most common culprits include milk, soy and grains. FPIES often develops in infancy, usually when a baby is introduced to solid food or formula.
Eosinophilic (ee-uh-sin-uh-fil-ik) Esophagitis (EoE) is an allergic condition causing inflammation of the esophagus. The esophagus is the tube that sends food from the throat to the stomach. Most research suggests that the leading cause of EoE is an allergy or a sensitivity to particular proteins found in foods. Many people with EoE have a family history of allergic disorders such as asthma, rhinitis, dermatitis or food allergy.
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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.
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Food Allergy Treatment & Management
Proper diagnosis of food allergy or food intolerance by an allergist / immunologist is the first step to managing your condition.
If you are diagnosed with a food allergy, the treatment plan will be to strictly avoid that food. If you are diagnosed with an intolerance, you may be able to ingest small quantities without having a reaction.
There is currently no cure for food allergies; nor are there medicines to prevent reactions. Yet there are steps you should take to manage your condition. The most important of these is avoiding coming in contact with food proteins that can cause an allergic reaction.
Read food labels to ensure that you don’t eat foods that contain foods to which you are allergic. Always ask about ingredients when eating at restaurants or when you are eating foods prepared by family or friends.
If you have severe allergies to food, be sure to complete an Anaphylaxis Action Plan and carry your autoinjectable epinephrine with you at all times. Use this medication in the event of an anaphylactic reaction.
For milder reactions, antihistamines may help relieve symptoms. Be sure to discuss this approach with your allergist / immunologist.
Food allergies can be confusing and isolating. Contact the Food Allergy & Anaphylaxis Network (FAAN) for patient support.
The Guidelines for the Diagnosis and Management of Food Allergy in the United States: Summary for Patients, Families, and Caregivers