What are the other Names of this Condition? (Also known as/Synonyms)

• Allergy to Eggs

What is Egg Allergy? (Definition/Background Information)

• Egg Allergy is a form of food allergy that manifests as an abnormal immune reaction/response to certain ingredients of egg (proteins in the egg whites or yellow), in individuals who consume them. Chicken eggs constitute the most common egg type causing an allergy
• Some individuals may tolerate egg albumin, some egg yolk; some who are allergic to chicken eggs, may develop allergy to other poultry products. The common egg-based products could include cakes, pasta, mayonnaise, egg cream, lecithin, etc.
• Egg Allergy may occur immediately, or after a few hours following exposure, which is through food ingestion. The egg may be in any form - poached, boiled, omelet, powder form, or eggnog. This condition is very common and it affects both children and adults
• Numerous signs and symptoms of the allergic reaction may be noted including runny nose, hives, sneezing, breathing difficulties, nausea and vomiting, and indigestion. In some rare cases, Egg Allergy may lead to an anaphylactic shock, which is a medical emergency
• Such food allergies are generally diagnosed using an antibody blood test, a skin-prick test, and an oral food challenge test. The diagnosis can also help identify egg-based food items that are to be avoided (in future)
• Anti-allergic medications form the first line of treatment for mild Egg Allergies. However, in the case of a severe allergic reaction (anaphylaxis), epinephrine or adrenaline injections are recommended
• The prognosis of Egg Allergy is generally good and most children overcome the condition during early or late childhood, although in some individuals it may be present lifelong. Awareness of such allergies and avoidance of specific foods that causes the allergy (via allergen-free foods) is the best form of prevention

Who gets Egg Allergy? (Age and Sex Distribution)

• Egg Allergies usually occur in infants and young children. The condition is seen in older children and adults too
• Studies indicate that the allergy peaks when a child is about 12 months’ old
• No gender preference is noted and both males and females are affected
• All racial and ethnic groups are equally vulnerable to the condition

What are the Risk Factors for Egg Allergy? (Predisposing Factors)

The risk factors for Egg Allergy may include:

• Consuming egg or egg products
• Any family history of an associated food allergy
• Atopic dermatitis, which is a form of eczema (skin condition)
• Infants and young growing children are more at risk
• Having one form of (food) allergy puts one at risk for other forms

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Egg Allergy? (Etiology)

An allergic reaction occurs in an individual with Egg Allergy, because the immune system recognizes certain proteins in egg as being dangerous and harmful to the body.

• The allergy may be to several components of the egg, to the yolk or albumin (egg whites). The causative proteins in eggs include albumin, lysozyme, and ovomucoid; other compounds include livetin and phosvitin
• Intake of food (protein) results in the production of antibodies, specifically immunoglobulin E (IgE). The next time the individual is exposed to the same protein, the antibodies that are circulating in blood causes an antibody-antigen reaction
• This results in the production of histamine and other chemical messengers, which cause the symptoms seen during an allergic reaction
• Young children are more prone to the condition, mostly due to an under-developed digestive system
• The quantity of food that triggers an allergy may not be significantly large. Sometimes, consuming tiny amounts of egg (allergen) is sufficient to trigger an Egg Allergy

In some cases, a severe allergic reaction termed as anaphylaxis may occur, which is a medical emergency that requires immediate medical attention.

Note: One may be allergic to non-food (egg) items including chicken embryo based vaccines (flu vaccines). Proteins in eggs may be also found in measles, mumps, and rubella (MMR) and yellow fever vaccines.

What are the Signs and Symptoms of Egg Allergy?

The signs and symptoms of Egg Allergy may start to appear within a few minutes, to a couple of hours, after the individual has consumed egg products. The symptoms are also common to other types of food allergies. In some, the symptoms are mild, while in others they are severe. A severe allergic reaction is a medical emergency, but it is typically rare.

The signs and symptoms of Egg Allergy may include:

• Itching of skin
• Urticaria (hives), skin rashes, or eczema
• Coughing, sneezing
• Shortness of breath (trouble breathing), wheezing, asthma-like symptoms
• Runny or stuffy nose
• Nausea and vomiting
• Diarrhea
• Abdominal distention (bloating)

Generally, not all episodes of allergy will be of the same severity. Rarely, in some individuals, the most severe symptom caused by Egg Allergies is anaphylaxis.

• Anaphylaxis (sometimes called an anaphylactic shock) is a life-threatening, whole-body allergic reaction
• During anaphylaxis, tissues in various body parts release histamine and other messenger chemicals, which causes swelling of the throat and other symptoms
• Swelling of the throat is especially dangerous as this can cause shortness of breath. If the swelling is not reduced soon, then there is a possibility that the individual could die from a lack of sufficient oxygen
• It can also result in a bluish skin, weak pulse, and decreased blood pressure (hypotension)

How is Egg Allergy Diagnosed?

The diagnosis of Egg Allergy may involve the following:

• Physical examination, assessment of symptoms, and medical history evaluation (history of allergies in the family)
• Food diary: Once an allergy is suspected, the healthcare provider may request to maintain a food diary, to note what is being consumed on a regular basis and the corresponding symptoms observed. The healthcare provider can help check which food products are causing allergy, through a process of elimination

The tests that are usually conducted to diagnose Egg Allergy include:

• Oral food challenge testing; when the individual is administered the allergens in a controlled manner to check for symptoms that develop
• Radioallergosorbent (RAS) test; to determine the specific allergy-causing substance
• Skin-prick test:
  • For this test, tiny amounts of certain substances are injected right underneath the skin (forearm, upper arm, or back)
  • After 15-20 minutes, if the spot where the chemical was injected swells, or if there is redness noticed, then this indicates that the individual may be allergic to the substance
• Blood test to detect antibodies (IgE antibody test)

Note: Do-it-yourself allergy testing kits that are commercially available are usually not recommended by healthcare providers.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Egg Allergy?

The complication of Egg Allergy is associated with the allergic reaction itself and it depends on the severity of the reaction. It may include:

• Anaphylactic shock/reaction that may be life-threatening
• Having one form of allergy can make the individual prone to other allergy types
• In severe reactions, a tracheostomy may have to be performed during an emergency situation 

How is Egg Allergy Treated?

The treatment of Egg Allergy may be undertaken in the following manner:

• Avoiding consumption of foods containing egg and egg products; elimination diets supervised by a qualified dietitian
• Anti-allergic medication for mild reactions; antihistamine therapy that is prescribed by the allergy physician
• Symptomatic treatment; use of decongestants, especially for nose block including steroid sprays
• In the case of anaphylaxis (severe allergic reaction), epinephrine or adrenaline is immediately administered
• Breathing support as necessary, control asthma symptoms and low blood pressure
• Immunotherapy, in case of severe allergies, for long-term tolerance development

Provide psychological support to children with such food allergies.

How can Egg Allergy be Prevented?

The best way to prevent Egg Allergy is to avoid egg and egg-based products that the individual is allergic to. Additionally, the following factors may be considered:

• Check ingredients of food before using; educate oneself on foods that potentially contain egg proteins
• Parents must be watchful and read food labels, to ensure they do not inadvertently give their child egg- containing foods
• Early introduction of eggs to babies, as recommended by a qualified healthcare consultant is known to prevent Egg Allergies (into the future)
• Studies have shown that breastfeeding children for 4-6 months or over, can help build their body immunity and make them less prone to allergies. However, if a child with a known allergy condition is being breastfed, then it is best to avoid eggs
• Appropriate maternal diet during pregnancy can help build stronger resistance (against allergies) in children
• Inform your healthcare provider about any allergies (especially Egg Allergy), prior to administering any vaccines
• Washing hands with soap and water, in case of contact with an allergen, especially before eating
• Avoiding contaminating food items with eggs during food preparation; use separate food utensils for preparing allergy-free meals, when possible
• Use alternatives to eggs, where possible
• While eating out, explain your food allergy to hotel/restaurant service staff and ensure that your food is without the substances you are allergic to
• In hotels and restaurants, separating the preparation of potential food allergens (such as egg, tree nuts, soy, fish) from general food preparation counters may be beneficial to individuals with food allergies. This can help avoid cross-contact (allergens getting transferred from one food type to another)
• Generating public awareness on various food allergies
• It is important to note that cooking to high-flame or cooking to recommended standards will NOT ensure elimination of the allergen

In case the child or adult is susceptible to an anaphylactic shock (high-risk individuals) from Egg Allergy, the following should be considered:

• Being watchful of triggers and avoiding them
• Wearing medical alert information bracelets or suitable devices
• Carry auto-injector epinephrine or adrenaline medications such as EpiPen, Anapen, or Twinject. Since the condition may recur, it is advised to carry 2 doses (2 pens)
• Supervise children on how to self-administer the injection, if required
• If child is prone to anaphylactic reaction, then information (preferably written instructions) should be given to day care, school authorities accordingly
• Adults should inform their spouses, colleagues, and friends, about the condition, in case of a future emergency

Presently, in many countries, due to labeling and consumer protection laws, foods have suitable labels that indicate their content.

What is the Prognosis of Egg Allergy? (Outcomes/Resolutions)

• The prognosis of Egg Allergy depends on the severity of the signs and symptoms, but it is generally good. Most cases resolve before 5 years in children, but sometimes later; over half outgrow the condition by age 17
• Some individuals may have it for the rest of their lives, but are able to cope well with modified diets that exclude eggs and egg products
• In some cases, the allergic reaction may be severe, causing anaphylaxis. This is a medical emergency that can lead to a respiratory failure. It requires an immediate treatment of the condition. In such cases, the prognosis is guarded and it depends on whether immediate medical assistance is provided

Additional and Relevant Useful Information for Egg Allergy:

Food product labels that show food ingredients starting with the prefixes “ova” or “ovo” may potentially contain egg-products.