Egg Allergy
Information on the causes, symptoms, and treatments for the immune system’s excessive reaction to egg consumption.
Symptoms and Causes
Egg allergy is an exaggerated immune response that occurs when this food is consumed, as the body identifies it as harmful despite being harmless (allergen). It is one of the most common types of food allergy in infants and children, although it can persist into adulthood.
Typically, the allergic reaction occurs specifically to egg white (yolk allergy is rare) and is more severe when the egg is cooked than when consumed raw. In most cases, the immune response is triggered by ovomucoid, a protein present in egg white that is highly resistant to heat and digestive enzymes. To a lesser extent, it can also occur in response to the protein ovalbumin.
The prognosis of egg allergy is favorable, as it usually resolves spontaneously before ages 7 to 9. Nevertheless, around 20% of patients continue to experience it in adulthood.
Symptoms
Symptoms of egg allergy usually appear shortly after ingestion, typically within 2 hours. The most common manifestations include:
- Itching in the mouth and throat
- Skin redness in the form of hives
- Rhinitis: nasal congestion, runny nose
- Conjunctivitis: red eyes, tearing
- Sensation of choking or difficulty breathing
- Asthma
- Nausea
- Vomiting
- Abdominal pain
Causes
The cause of egg allergy, as with all types of allergies, is an error of the immune system that reacts disproportionately to egg or one of its components.
Risk Factors
The risk of developing egg allergy is higher in the following cases:
- Age: usually manifests before 2 years and, in most cases, resolves before age 9
- Personal or family history of allergies
- Atopic dermatitis
Complications
The most serious complication of egg allergy is anaphylaxis, a severe reaction that can be life-threatening, as it may cause:
- Inflammation of the airways, tongue, or lips
- Hypotension
- Cardiac arrhythmias
- Dizziness
- Fainting or loss of consciousness
Prevention
The only way to prevent this type of allergy is to avoid egg consumption. It is therefore essential to carefully read food labels and exercise caution when eating outside the home.
Which Specialist Treats Egg Allergy?
Egg allergy is managed by an allergology specialist.
Diagnosis
The diagnosis of egg allergy usually includes the following procedures:
- Medical history: all relevant information about the patient’s medical and family history is collected, as well as details of symptoms and their timing.
- Skin prick test: drops of the egg allergen are applied to the forearm with a small puncture to allow penetration into the skin. After a set time, the skin is examined. Redness and swelling indicate that the patient is allergic to egg or one of its components.
- Blood test: a blood sample is taken to detect specific antibodies against the allergen proteins.
- Oral food challenge: under medical supervision, the patient ingests a small amount of egg, and the response is monitored. The dose is gradually increased to assess how the allergen affects the body. If no abnormal response occurs, allergy is ruled out.
Since children often develop tolerance to egg over time, follow-up visits are scheduled to monitor progress in each case.
Treatment
Once egg allergy is diagnosed, the patient must completely avoid egg consumption. Symptom management includes:
- Oral medication: antihistamines or corticosteroids are administered to reduce inflammation and relieve itching.
- Injectable medication: intramuscular epinephrine is effective in cases of anaphylaxis, reducing inflammation, raising blood pressure, and opening airways.
- Oral immunotherapy or tolerance induction: an innovative approach in which increasing doses of egg are ingested under medical supervision until the patient can tolerate consumption. Supportive medication is used to ensure safety. Once the maximum tolerated dose is reached, medication is discontinued, and a maintenance phase at home is initiated, during which the stipulated egg dose must be consumed to maintain tolerance.
