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Egg Allergy: Symptoms, Testing and Management

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By Dr.Divya Goil

 

  • Egg allergies are seen predominantly, but not exclusively, in children.
  • It is estimated that roughly half of these children outgrow their egg allergy.
  • Like other food allergies, it is mostly an IgE-mediated response to a specific protein in the food.

 

Etio-Pathogenesis

Egg allergies, like other allergies, are mostly an IgE-mediated immune response to a specific protein constituent of eggs. Family history of allergies and other concurrent allergies, particularly atopic dermatitis, are risk factors for developing food allergies.

 

Signs & Symptoms of Egg Allergy

Cutaneous manifestations are the most common for food allergies.

  • Pruritus and Urticaria are the most common.
  • Angioedema (eg, laryngeal edema).
  • Gastrointestinal symptoms like nausea, vomiting, diarrhea, abdominal pain.
  • Respiratory symptoms like stridor, cough, dyspnea, wheeze.
  • Conjunctival edema, periocular edema.
  • Nasal congestion, nasal pruritus, rhinorrhea, and sneezing.
  • Feeling of impending doom, flushing, cardiovascular collapse.
  • Anaphylaxis

 

How To Test For Egg Allergy?

Skin Prick Testing and allergen-specific IgE serum assays are the primary clinical tests for diagnosing egg allergy. However, these test results must be corroborated with a sound history-taking and a diet diary.

 

1. Skin Prick Testing 

It is a widely performed test as it is inexpensive, minimally invasive, done on an OPD basis with minimal risk to the patient, and used to test for a wide range of allergens. The results from SPT are quick and easily reproducible making it invaluable in allergen diagnosis.

The utilization of the right allergen proteins, with the right methodologies & proper controls, and ensuring avoidance of interfering medication is essential to a reliable result. The SPT has a 90% negative predictive value and is extremely useful for excluding non-IgE mediated differentials. 

However, despite availability, this test is not performed often enough in India due to a lack of expertise, knowledge of its importance, or resources. In fact, our course, the Allergy Asthma Certificate Course was built to bridge these gaps in Allergy management in South-East Asia.

2. Specific IgE antibodies

Allergen-specific IgE antibodies can be detected in the patient's blood sample. This test is highly predictive of an IgE-mediated allergic disorder.

However, it is more time-consuming and invasive than a Skin Prick Test. As with the SPT, corroboration with the history of the illness is essential to diagnosis. 

Component testing is an emerging diagnostic tool wherein the specific offending component of the offending protein is identified. This has clinical significance in that certain foods containing the offending protein can be allowed in the patient's diet based on whether inactivation properties of that component to that cooking method.

3. Oral Challenge Test

After a period of eliminating the suspect food from the patient's diet, the physician reintroduces and feeds it to them gradually. If symptoms occur, this is stopped and the patient treated.

 

Although this is the gold standard for testing for egg allergies, it is generally avoided because of the risk of a severe reaction. It is preferred only when the results of the Skin Prick Test and Specific IgE test are inconclusive.

 

Management of Egg Allergy

  • Elimination of eggs and egg-containing foods is of primary importance. The patient and their family should be educated on common egg-containing foods and on how to read food labels. Separate cooking without utensil sharing for eggs should be ensured. People with egg allergies are often also allergic to chicken.

 

  • An emergency plan should be discussed that should be articulated to the patient's extended family/school/workplace/other frequent places of visit. The patient's details with the allergens details and an emergency contact should be worn on the patient's body. The patient should always have self-injectable epinephrine and the patient and their family and friends should be taught how to use it. 

 

The lack of importance given to allergy management in the curriculum of medical colleges in South-East Asia has led to suboptimal diagnosis and management of allergic disorders despite allergic disorders being vastly prevalent throughout the country. If you would like to learn more, have a look at our Resources and other Blog posts as well. We also offer a comprehensive online course - the Allergy Asthma Certificate Course - for doctors interested in practicing specialist allergy management for their patients.

 

Egg Allergy FAQs For Patients: 

Q. What Causes Egg Allergies?

Allergies occur when a body wrongly detects a harmless substance as being harmful and mounts an immune response against it. People with a family history of allergies and other concurrent allergic conditions are at greater risk.

Q. How Long Do Allergy Symptoms Last?

Allergic reactions can last from a few hours to a few days, and in certain cases even up to a few weeks - especially if allergen exposure is continuous.

Q. How Do You Get Rid Of Egg Allergy?

It is estimated that roughly half of the children with an egg allergy outgrow it by the age of 7. If it persists, avoidance of eggs and emergency management are essential.

Q. How Do You Manage Egg Allergies?

Complete elimination of eggs and egg-containing products is recommended. If eggs are a major part of the patient's diet, alternatives to substitute for the nutrients eggs were providing them must be added to their diet. An emergency plan must be discussed with your allergist and implemented. Treatment measures should be decided based on your allergists' recommendations.