An allergy refers to an exaggerated reaction of your immune system in response to certain foreign substances. These foreign substances, commonly known as allergens, present in the environment are usually harmless to most people and they do not produce a reaction in nonallergic people. Dust mites, pollen, ticks, moulds, proteins, certain medications certain foods are common examples of allergens.

If you are allergic to a particular allergen, then your body recognizes that foreign substance as harmful and your immune system generates an exaggerated immune response. Most allergic reactions/symptoms like itchiness, redness of the skin, rashes, nausea, etc. are mild to moderate and do not cause major problems. 

Allergies are categorized into different types based on the cause or allergen such as:

  • Seasonal allergy, also called ‘hay fever’ or ‘allergic rhinitis’, are allergy symptoms that happen during certain times of the year only (in a particular season). 

  • Food allergy is an unpleasant or dangerous immune system reaction after you eat a certain food.

  • Drug allergy is an abnormal reaction to a medication.

  • Insect-bite allergy is an immune reaction caused by insect bites of bugs, cockroaches, millipedes, fleas, certain flies, crabs, or scorpions.

In this article, we will understand about egg allergy, a common type of food allergy. 

What is a food allergy?

When you eat something you're allergic to, your immune system responds to protect you. Common foods that trigger allergic reactions are milk (mostly in children), eggs, nuts (walnuts, almonds, Brazilian nuts), peanuts, wheat, fish, and shellfish (mostly in adults). Corn, gelatin (a colorless & flavorless food ingredient derived from collagen), and seeds (sunflower or sesame) are less common foods that can also cause allergic reactions.

What is an egg allergy?

Egg allergy is an immune hypersensitivity to proteins found in chicken eggs, and possibly goose, duck, or turkey eggs. Egg allergy is one of the second most common food allergies in children and some adults. Allergic reactions on ingestion of eggs may range from mild reactions to life-threatening anaphylactic shock (also known as anaphylaxis) in children and adults. In anaphylaxis, the symptoms are more severe than in regular allergic reactions, such as dizziness, fainting, low blood pressure, rapid heartbeat, nausea, vomiting, trouble breathing, or cardiac arrest. 

Fortunately, some studies show that about 70% of children with an egg allergy outgrow their symptoms by 16 years of age.

What causes an egg allergy?

Egg allergies happen when the immune system mistakenly identifies certain egg proteins as harmful substances. 

Your immune system is a wide network of cells and tissues that are always on the lookout for invaders (foreign substances such as egg proteins here) and are ready to attack (launch an immune response) when they find one. 

When you and your child come in contact with egg proteins, immune system cells recognize them and signal other cells of the immune system to release histamine (compound involved in local immune responses) and other chemicals that cause allergic signs and symptoms. 

Both egg white (the clear, thick liquid that surrounds the bright yellow yolk of an egg) and egg yolk (the yellow part at the center of an egg) contain protein that can cause allergies, but an allergy to egg white is more common. If a mother consumes eggs, it is possible for breastfed infants to have allergic reactions to egg protein in breast milk.

What are the symptoms of an egg allergy?

Allergy symptoms might develop within minutes to a few hours after eating eggs or food containing eggs.

Mild reactions include:

  • Hives (red, pink, or flesh-colored itchy skin rashes)

  • Nasal allergy (an allergic response causing itchy, watery eyes, sneezing, and other similar symptoms)

  • Nausea, vomiting, and abdominal cramps

  • Asthma (a condition in which your airways narrow and swell) signs and symptoms such as coughing, chest tightness, or shortness of breath 

Severe allergic symptoms include:

  • Life-threatening anaphylactic shock, with a sudden drop in blood pressure, resulting in dizziness,  lightheadedness, or loss of consciousness.

How is an egg allergy diagnosed?

Your doctor will start with collecting your or your child’s medical history and conduct a detailed physical examination. Depending on your symptoms, your doctor may recommend one or more of the following tests:

  • Allergy skin prick test. Skin prick test is done by placing a small drop of allergen on your skin, preferably on your forearm. The skin is then pricked with a lancet so that the allergen can go inside the layers of your skin. The whole process does not cause any pain or bleeding. Then a nurse watches the site carefully for any sign of swelling and redness which is usually seen within 15 to 20 minutes of ingesting the allergen. To test for egg allergy, the above process is performed with an egg allergen.

  • Allergy blood test. A blood test can measure your immune system's response to eggs by checking the number of certain antibodies in your bloodstream that may indicate an allergic reaction. In this test, your blood sample is collected and sent to the laboratory for testing for certain foods.

  • Food challenge. This test involves giving you or your child a small amount of egg to see if it causes a reaction. If nothing happens after the first round of intake of egg, more egg is given while the doctor watches for signs of a food allergy. Food challenges can be risky and should be performed by trained allergists (a physician who specializes in the diagnosis and treatment of allergies) only.

  • Food tracking and elimination diet. Your doctor plans food elimination and a challenging diet, based on the severity of allergy symptoms and the number of foods you are allergic to. You need to keep a detailed diary of the consumed foods and you may be asked to eliminate certain foods to see whether your symptoms improve.

Allergy blood and skin tests are often used along with the food challenge and diet changes. If your doctor suspects that symptoms may be caused by something other than a food allergy, your child may or might need to take more tests to identify or rule out other possible causes.

How is an egg allergy treated?

1. Antihistaminics (drugs that can relieve allergy symptoms). Medications such as antihistamines are the common line of treatment for mild symptoms such as skin rashes and itching.

2. Adrenaline injection. Adrenaline is injected into your outer mid-thigh muscle by an auto-injector to reduce symptoms of anaphylaxis (a potentially fatal reaction that includes shortness of breath, swelling of the throat, and dizziness) and maintain heart function and blood pressure. 

3. Vaccines that do not contain egg proteins. Certain vaccines contain egg proteins. If you’re allergic to eggs, make sure to take vaccines that don’t contain egg proteins and are approved for use for people 18 years of age and above. 

Most children eventually outgrow egg allergy. Talk to your child's doctor about the frequency of testing to see whether eggs still cause symptoms.

How can you prevent an egg allergy?

The only way to prevent egg allergy symptoms is to avoid eggs or egg products.

  • Know what you are eating or drinking. Read labels carefully and be cautious when you are eating out.

  • Make sure your child’s caregiver, like a babysitter, teacher, and relative, knows about your child’s sensitivity to eggs. Instruct them to be careful while feeding your baby.

  • If you are breastfeeding your baby, avoid eating eggs. Breastfeeding, also known as nursing, is the feeding of babies and young children with milk from a woman's breast.  

  • If you wish, your baby and you can wear an allergy bracelet or band or a badge that says, “I am allergic to eggs”, to make sure others around your child and you are aware and alert.

How to read food labels to avoid foods that contain egg 

If you have an egg allergy, watch out for the following ingredients on various food labels:

  • Albumin/ Albumen      

  • Egg (dried, powdered, solids, white, yolk)      

  • Eggnog      

  • Globulin       

  • Livertin        

  • Lysozyme       

  • Mayonnaise        

  • Meringue        

  • Surimi       

  • Vitellin        

  • Words starting with ova such as ovalbumin or ovoglobulin 

An egg is sometimes found in the following foods:     

  • Baked goods

  • Bakery  items

  • Drink foams (foam on top of cocktail) such as alcoholic drinks or specialty coffee     

  • Egg substitutes     

  • Fried rice      

  • Ice cream        

  • Lecithin supplements are usually derived from sunflower seeds, eggs, or soybeans        

  • Marzipan (confectionary food item consisting primarily of sugar or honey and almond meal)      

  • Marshmallows      

  • Meatloaf and meatballs        

  • Nougat        

  • Pasta   

Remember that while it's mostly the whites of an egg that contains the allergenic proteins, patients with an egg allergy must avoid all eggs completely. In case your child or you have consumed eggs without knowledge, watch out for symptoms and see how severe they get. Consult your general physician immediately if the symptoms are worsening for the next steps.

Disclaimer: This article is written by the Practitioner for informational and educational purposes only. The content presented on this page should not be considered as a substitute for medical expertise. Please "DO NOT SELF-MEDICATE" and seek professional help regarding any health conditions or concerns. Practo will not be responsible for any act or omission arising from the interpretation of the content present on this page.