Eggs in themselves aren't bad, but when someone is allergic to them, the body thinks they are. When a person is allergic to eggs, the body's immune system overreacts to proteins in the egg. So every time something made with eggs enters the digestive system, the body thinks that these proteins are harmful invaders.

The immune system responds by creating specific antibodies to that food, which are designed to fight off the "invader." These antibodies — called immunoglobulin E (IgE) — trigger the release of certain chemicals into the body, one of which is histamine.

So when a child with an egg allergy eats a food that contains eggs, the immune system unleashes an army of chemicals to protect the body. The release of these chemicals can affect the respiratory system, gastrointestinal tract, skin, and the cardiovascular system — causing allergy symptoms like wheezing, nausea, headache, stomachache, and itchy hives.

Most people who are allergic react to the proteins in egg whites, but some can't tolerate proteins in the yolk. Egg allergy usually first appears when kids are very young, and most kids outgrow it by the time they're 5 years old.

Egg allergy is like most food allergy reactions: It usually happens within minutes to hours after eating eggs. Most reactions last less than a day and may affect these three body systems:

· the skin: in the form of red, bumpy rashes (hives), eczema, or redness and swelling around the mouth

· the gastrointestinal tract: in the form of belly cramps, diarrhea, nausea, or vomiting

· the respiratory tract: symptoms can range from a runny nose, itchy, watery eyes, and sneezing to the triggering of asthma with coughing and wheezing

Most kids with egg allergy have some of the reactions listed above, but a few may have a very strong reaction called anaphylaxis. This severe allergic reaction causes swelling of the mouth, throat, and airways leading to the lungs, resulting in breathing difficulty. In addition, there is a dangerous drop in blood pressure, which can make a child dizzy or pass out, and may quickly lead to shock.

If your doctor suspects your child might have an egg allergy, he or she will probably refer you to an allergist or allergy specialist for further testing. The allergy specialist will ask things like how often your child has the reaction, the time it takes between eating a particular food and the start of the symptoms, and whether any other family members have allergies or conditions like eczema and asthma.

The allergy specialist may perform a skin test. This test involves placing liquid extracts of egg protein on a child's forearm or back, pricking the skin a tiny bit, and waiting to see if a reddish, raised spot forms, indicating an allergic reaction.

Your child will need to stop taking anti-allergy medications (such as over-the-counter antihistamines) 5 to 7 days before the skin test because they can interfere with the results. Most cold medications as well as some antidepressants may also affect skin testing. Check with the allergist's office if you're unsure about what medications need to be stopped and for how long.

Some doctors may also take a blood sample and send it to a lab where it will be mixed with some of the suspected allergen and checked for IgE antibodies.

In some cases, however, positive results of skin and blood tests aren't enough to prove that symptoms are definitely being caused by eggs. So doctors may use what's called a food challenge to help diagnose the allergy.

With a food challenge, the person will eat foods that contain eggs only under close supervision from a doctor. If symptoms appear after eating egg products, it's likely the person has an egg allergy.

Treating egg allergy might seem simple — just make sure your child doesn't eat eggs. But so many foods are made with eggs and egg products that it can be really hard to know what's OK and not OK to eat. Consider working with a registered dietitian to develop an eating plan that provides all the nutrients your child needs while avoiding things made with eggs.

If your child has a severe egg allergy — or any kind of serious allergy — your doctor may want you to carry a shot of epinephrine with you in case of an emergency. Epinephrine comes in an easy-to-carry container about the siz​e of a large marker. It's easy to use — the doctor will show you how to give a shot to your child should you ever need to.

If your child accidentally eats something with egg in it and starts having serious allergic symptoms, like swelling inside the mouth, chest pain, or difficulty breathing, give the shot right away to counteract the reaction while you wait for medical help. Always call for emergency help (911) if your child has needed to use epinephrine. Besides keeping epinephrine in your home, briefcase or purse, also be sure it's at relatives' homes and at daycare or school.

Also carry an over-the-counter antihistamine as this can help alleviate allergy symptoms in some kids. Antihistamines should be used in addition to the epinephrine and not as a replacement for the shot.

If your child has had to have an epinephrine shot because of an allergic reaction, go immediately to a medical facility or hospital emergency room so they can provide additional treatment if needed. Up to one third of anaphylactic reactions can have a second wave of symptoms several hours following the initial attack. So your child might need to be observed in a clinic or hospital for 4 to 8 hours following the reaction.

The best way to be sure a food is egg free is to read the label. Manufacturers of foods sold in the United States must list on their labels whether a food contains any of the most common allergens. So look for statements like these somewhere on the label: "contains egg ingredients," "made using egg ingredients," or "made in a facility that also processes eggs."

This label requirement makes things a little easier than reading the ingredients list — instead of needing to know that the ingredient "ovoglobulin" comes from egg protein, you should be able to tell at a glance which foods to avoid.

Still, to make sure the foods your child eats are egg free, you'll need to be on the lookout for any ingredients that might come from eggs. That means asking questions when eating out at restaurants or others' homes and carefully reading food labels.

Try to find out how foods are cooked and what's in them. In some cases, you may want to bring your child's own food with you. When you're shopping, look for egg-free alternatives to foods that usually contain eggs, such as pasta.

· 1 teaspoon baking powder + 1 tablespoon liquid + 1 tablespoon vinegar

· 1 teaspoon yeast dissolved in ¼ cup warm water

· 1½ tablespoons water + 1½ tablespoons oil + 1 teaspoon baking powder

· 1 packet gelatin + 2 tablespoons warm water (don't mix until ready to use)

· 1 tablespoon pureed fruit such as apricots or bananas

Although the number of people in the United States with food allergies is low (just over 1% of the total population), there's a growing awareness about food allergies. This means that everyone — from the waitstaff at a restaurant to food manufacturers — is more understanding and willing to accommodate a child's food needs.

Reviewed by: Nathan B. Richards, MD, and Sheelagh M. Stewart, RN, MPH

Date reviewed: October 2011