Food Allergy

Food Allergy

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A food allergy occurs when a child’s immune system mistakenly attacks a harmless food protein. Food allergies can be serious medical conditions. They affect up to 15 million people in the United States, including one in 13 children.

During an allergic reaction, the immune system produces abnormally large amounts of an antibody called immunoglobulin E — IgE for short – and antibodies fight the food allergens by releasing histamine and other chemicals, triggering symptoms.

The most common food allergens are the proteins in cow’s milk, eggs, peanuts, wheat, soy, fish, shellfish and tree nuts. In some food groups, an allergy to one member of a food family may result in allergies to other members of the same group. This is known as cross-reactivity.

The most severe allergic reactions are often associated with peanuts, tree nuts and shellfish. Food allergies are increasing among children, and there are several hypotheses as to why, though none have been proven:

  • The hygiene hypothesis – Developed lifestyles with decreased exposure to bacteria may disrupt the normal development of the immune system.
  • Delayed Introduction of allergenic foods – Studies have indicated that introduction of some foods, like peanut, into the diet early in life before allergy has developed, may decrease the risk of developing an allergy to that particular food.
  • Forms of food – Different forms of the same food – roasting vs. boiling vs. baking, for example – can provoke different reactions (or no reactions) from known allergic people.
  • Increased awareness and reporting.

Allergy-Immunology is a unique medical field that covers a broad span of diagnoses. The physicians at Children’s Health can help your child cope with allergic conditions as well as deficiencies in your child’s immune system. The Food Allergy Center at Children’s treats a broad range of allergic diseases and conducts research instrumental in the development and treatment of children with food allergies.

Symptoms

Symptoms

Symptoms of a food allergy usually appear within minutes to hours of consuming an allergen. Mild food allergy symptoms include hives (reddish, itchy areas on the skin), eczema (a dry, itchy rash), itchy mouth or throat, nausea or diarrhea, dry cough and swelling around the eyes or on the face.

Severe symptoms may include one or more of the following:

  • Obstructive swelling of the throat, tongue or lips
  • Trouble breathing or swallowing
  • Wheezing
  • A drop in blood pressure causing fainting or weakness
  • Chest pain
  • A weak pulse
  • Loss of consciousness

Anaphylaxis is a severe, and potentially fatal, allergic reaction. Someone suffering from anaphylaxis usually has symptoms that involve the skin, nose, mouth, or gastrointestinal tract as well as difficulty breathing or reduced blood pressure (leading to paleness, confusion, loss of consciousness). Anaphylaxis must be treated immediately with epinephrine (adrenaline), a shot that reverses severe symptoms. The anaphylaxis sufferer should then be taken to the emergency room.

Tests and Diagnosis

Tests and Diagnosis

Your child’s doctor will ask detailed questions about allergy symptoms and history. The doctor may consider ordering a blood test and/or perform skin prick food allergy tests, which indicate whether food-specific IgE antibodies are present in your child’s body.

Skin prick tests can usually be administered in a doctor’s office and provide results within 15 to 30 minutes. A nurse or doctor will prick your child’s skin with a sterile lancet that contains a tiny amount of food allergen. The tests are considered positive if a bump develops at the site.

If your doctor orders blood tests, your child will have blood drawn at a lab and results will be available in about a week.

Based on the results of these tests and reported symptoms, your child’s doctor will determine if your child is likely to be allergic to the food or is likely to be able to tolerate the food without having an allergic reaction. If it remains unclear whether your child is allergic or tolerant to the food in question, your doctor may recommend an oral food challenge. In this procedure, your child is fed a serving of the food in question under strict supervision in the Food Allergy Center so that if a reaction does occur it may be recognized promptly and treated appropriately.

Treatments

Treatments

If your child is allergic to a food, he or she must avoid the allergenic food, and both children and caregivers should be educated on how to avoid these foods and how to administer epinephrine in the case of accidental exposure.

Some children outgrow, or have less severe reactions with, allergies to eggs or cow’s milk, but peanut, tree nut, fish, and shellfish allergies seem to be long-lasting.

Because serious, or even fatal, reactions may occur outside the home, you – as a parent or caregiver – must ensure your child’s school, coaches, babysitters, friends’ parents, chaperones on field trips and others have written knowledge of the allergy, emergency plans and access to epinephrine.

You may meet with a registered dietitian to discuss avoidance and nutritional supplementation for your child.

FAQs

FAQs

What are the chances of my child outgrowing a food allergy?

Most children will outgrow allergies to milk, eggs, soy, and wheat but outgrowing allergies to peanuts, tree nuts, fish and shellfish is less common.

What is the difference between food allergy and food intolerance? 

A food intolerance occurs when your digestive system cannot handle a certain type of food, typically due to a missing enzyme. An intolerance may present some of the same gastrointestinal symptoms as a food allergy, but only a food allergy involves an allergic response from the body's immune system.

Where can I find a support group?

We will provide you with resources to help both you and your child. The Resources link on this webpage is also a good source for more information about food allergies and support groups.

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