Egg alergy

Symptoms

Egg allergy symptoms differ from person to person and occur within a few minutes to a few hours after exposure to eggs. Egg allergy symptoms can include:

• Skin inflammation or hives, the most common egg allergy reaction
• Allergic asthma
• Allergic nasal inflammation (rhinitis)
• Gastrointestinal symptoms, such as cramps, nausea and vomiting

Anaphylaxis

Egg allergy can cause anaphylaxis, a life-threatening reaction that can block the airways and breathing. If you or your child has a reaction to eggs, tell your doctor about it no matter how mild the reaction may have been. Tests can help confirm an egg allergy, so you can take steps to avoid future and potentially worse reactions.

Anaphylaxis is a medical emergency and requires treatment with an epinephrine (adrenaline) shot and a trip to the emergency room. Signs and symptoms start soon after eating eggs and can include:

• Constriction of airways, including a swollen throat or a lump in your throat that makes it difficult to breathe
• Shock, with a severe drop in blood pressure
• Abdominal pain and cramping
• Rapid pulse
• Dizziness, lightheadedness or loss of consciousness

Causes

All food allergies are caused by an immune system malfunction. Your immune system mistakenly identifies certain egg proteins as harmful, triggering the production of immunoglobulin E (IgE) antibodies to neutralize the protein (allergen). The next time you come in contact with these proteins, these IgE antibodies recognize them and signal your immune system to release histamine and other chemicals. Histamine and other body chemicals cause a range of allergic signs and symptoms. Histamine is partly responsible for most allergic responses, including runny nose, itchy eyes, dry throat, rashes, hives, nausea, diarrhea, labored breathing and anaphylactic shock.

Both egg yolks and egg whites contain a number of proteins that can cause allergies, but allergy to egg white is more common. It's possible for breast-fed infants to have an allergic reaction to egg proteins in breast milk.

Risk factors

Certain factors may put you at greater risk of developing an egg allergy:

• Other allergies. Sometimes egg allergy occurs in association with other allergies.
• Atopic dermatitis. Children with this type of eczema are much more likely to develop a food allergy.
• Family history. You're at increased risk of a food allergy if one or both of your parents have asthma, food allergy or another type of allergy — such as hay fever, hives or eczema.
• Age. Egg allergy is more common in children. As you grow older, your digestive system matures and your body is less likely to absorb food or food components that trigger allergies. Most children outgrow an egg allergy by the time they're 5 years old.

Complications

Children who are allergic to eggs are more likely to develop certain other health problems, including:

• Allergies to other foods — such as milk, soy or peanuts
• Hay fever — a reaction to pet dander, dust mites or grass pollen
• Atopic dermatitis
• Allergic asthma

Diagnosis

To evaluate whether you or your child has an egg allergy, your doctor may:

• Ask detailed questions about signs and symptoms
• Perform a physical exam
• Have you keep a detailed diary of the foods you or your child eats
• Have you eliminate eggs from your diet or your child's diet (elimination diet) — and then have you eat the food in question again to see if it causes a reaction

Your doctor may also recommend one or more of the following tests:

• Skin test. In this test, your skin is pricked and exposed to small amounts of the proteins found in eggs. If you're allergic, you develop a raised bump (hive) at the test location on your skin. Allergy specialists usually are best equipped to perform and interpret allergy skin tests.
• Blood test. A blood test can measure your immune system's response to eggs by measuring the amount of certain antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies. A blood sample can be tested in a medical laboratory, where it can be tested for evidence of sensitivity to eggs.
• Food challenge. Because other tests aren't always conclusive, your doctor may want to do a food challenge. This test involves giving small amounts of the offending food and then monitoring the child or adult for a reaction. If no reaction occurs, more of the substance is given, and you or your child will again be monitored. One reason for doing a food challenge could be to confirm that your child has outgrown his or her allergy to eggs.

If your doctor suspects your problems are caused by something other than a food allergy, you may need other tests to identify — or rule out — other medical problems.

Treatments and drugs

The only way to prevent an egg allergy is to avoid eggs or egg products altogether. This can be difficult, as eggs are a common food ingredient. You may find that your child can tolerate eggs that have been cooked into foods, such as baked goods.

Additionally, some people who are allergic to chicken eggs are also allergic to other kinds of bird eggs — such as duck, turkey, goose or quail eggs. In some cases, people who are allergic to eggs are also allergic to chicken. This is known as bird-egg syndrome.

Despite your best efforts, you or your child may still come into contact with eggs. Medications, such as antihistamines, may reduce signs and symptoms of a mild egg allergy. These drugs can be taken after exposure to eggs to control an allergic reaction and help relieve discomfort.

If you or your child has a serious allergic reaction (anaphylaxis), you may need an emergency injection of epinephrine (adrenaline) and a trip to the emergency room. If you're at risk of having a severe reaction, you or your child may need to carry injectable epinephrine (EpiPen) at all times.

The good news is that most children with an egg allergy will eventually outgrow it.

Prevention

There is no sure way to prevent a food allergy from occurring in the first place — but you can avoid unpleasant or dangerous reactions by avoiding the foods that cause them. If you know you or your child is allergic to eggs, the only sure way to avoid an allergic reaction is to avoid all egg products. Know what your child is eating and drinking. Be sure to read food labels carefully.

If you or your child is at risk of a serious allergic reaction, talk with your doctor about carrying and using emergency epinephrine (adrenaline). If you or your child has already had a severe reaction, wearing a medical alert bracelet or necklace is a good way to make others aware of a food allergy.

People allergic to eggs may also have a reaction after their skin comes in contact with eggs, so avoid touching eggs or products that contain eggs.

Egg allergy and flu vaccinations

Because flu vaccines contain small amounts of egg proteins, there is some risk of an allergic reaction if someone with egg allergy receives a flu (influenza) vaccine. However, many influenza vaccines contain such small amounts of egg protein that they can be safely given to people with an egg allergy. If you or your child has had a reaction to eggs, talk to your doctor before getting a flu shot. Your doctor may give you or your child a test to determine whether the vaccine is likely to cause a reaction. Other vaccinations contain little or no egg protein. But tell your doctor if you or your child has had an allergic reaction to eggs in the past, just to be safe.

Hidden sources of egg products

While there's no sure way to prevent an allergic reaction to eggs, reading labels, being cautious when eating out, and using egg-free products can help you or your child avoid an unpleasant or dangerous reaction. Unfortunately, even if a food is labeled egg-free it may still contain allergy-causing egg proteins. When in doubt, contact the manufacturer to be sure a product does not contain eggs.

Food products that contain eggs:

• Marshmallow
• Mayonnaise
• Meringue

Other foods that may contain eggs include:

• Baked goods
• Mixes, batters and sauces
• Frostings
• Processed meat, meatloaf and meatballs
• Pudding
• Salad dressing
• Many pastas
• Root beer and specialty coffee or alcoholic drinks

People who are very sensitive to egg proteins have a reaction when they touch eggs or egg products. Nonfood products that sometimes contain egg include:

• Shampoo
• Medications
• Cosmetics
• Finger paints

Several terms indicate that egg products have been used in manufacturing processed foods. Terms that imply egg protein is present include:

• Albumin
• Globulin
• Lecithin
• Livetin
• Lysozyme
• Simplesse
• Vitellin
• Words starting with "ova" or "ovo," such as ovalbumin or ovoglobulin

Another potential source of exposure is cross-contamination in home-prepared dishes or meals, especially when you're eating in other people's homes where they may not be aware of the risk.

References:

https://www.foodallergy.org/allergens/egg-allergy

http://acaai.org/allergies/types/food-allergies/types-food-allergy/egg-allergy

http://kidshealth.org/en/teens/egg-allergy.html

http://www.healthline.com/health/allergies/egg

https://en.wikipedia.org/wiki/Egg_allergy

http://www.kidswithfoodallergies.org/page/egg-allergy.aspx