Egg allergy is an immune system malfunction where the body mistakenly identifies egg proteins as a threat, leading to the production of Immunoglobulin E (IgE) antibodies. This overreaction causes various physical symptoms upon ingestion. As infants begin exploring solid foods, egg allergy frequently emerges, establishing it as one of the most common food allergies seen in early childhood.
Prevalence and Primary Risk Factors
The prevalence of egg allergy in the infant population is notable, affecting approximately 0.5% to 2.5% of young children. In some studies focusing on one-year-old infants, the rate of raw egg allergy can be as high as 9.5%, though this figure drops significantly as children age. Egg allergy is often the second most common food allergy in young children, following cow’s milk allergy. A significant risk factor is a family history of allergic diseases, such as asthma, allergic rhinitis, or other food allergies, suggesting a genetic predisposition. Another indicator is the presence of other allergic conditions in the baby, particularly atopic dermatitis (eczema).
Recognizing the Signs of an Allergic Reaction
An allergic reaction to egg typically appears quickly, within minutes to a couple of hours after ingestion. The most common symptoms involve the skin, presenting as hives (raised, red, and itchy welts), general flushing, or swelling of the lips, face, or around the eyes. Existing eczema may also suddenly flare up or worsen following exposure. Gastrointestinal symptoms include vomiting, stomach cramps, and diarrhea. Respiratory symptoms, such as wheezing, a persistent cough, or difficulty breathing, can signal a more severe reaction and necessitate immediate medical attention, especially if multiple body systems are involved.
Medical Confirmation and Diagnostic Procedures
Diagnosis begins with a detailed clinical history, reviewing symptoms, timing, and the amount of egg consumed. This history helps differentiate a true immune-system allergy from a food intolerance. The Skin Prick Test (SPT) is a quick procedure where a small amount of liquid egg allergen is placed on the skin; a positive result is a raised, hive-like bump. Specific IgE blood tests also measure egg-specific IgE antibodies in the bloodstream, indicating sensitization. The Oral Food Challenge (OFC) remains the definitive diagnostic tool, involving the supervised feeding of gradually increasing amounts of egg in a medical setting to monitor for any reaction and ensure access to emergency care.
Management Strategies and Prognosis for Resolution
The primary management strategy for a diagnosed egg allergy is the strict avoidance of all forms of egg, requiring careful label reading. For children with moderate or severe reactions, a physician will prescribe an emergency action plan, including an epinephrine auto-injector (EpiPen) that must be readily available. The long-term outlook is positive, as egg allergy is one of the most commonly outgrown food allergies. Roughly 50% of children develop tolerance by two years of age, and 80% to 90% have outgrown the allergy by school age. Factors suggesting persistence include early-onset severe eczema, multiple food sensitizations, and a large wheal size on the Skin Prick Test; the ability to tolerate baked egg products is a positive indicator of resolution.