The heat of cooking structurally degrades protein molecules, potentially making them less allergenic.The pathophysiology of allergic responses can be divided into two phases. The first is an acute response that occurs within minutes to an hour or two exposure to an allergen. This phase can either subside or progress into a "late-phase reaction" which can substantially prolong the symptoms of a response, and result in more tissue damage. In the early stages of acute allergic reaction, lymphocytes previously sensitized to a specific protein or protein fraction react by quickly producing a particular type of antibody known as secreted IgE (sIgE), which circulates in the blood and binds to IgE-specific receptors on the surface of other kinds of immune cells called mast cells and basophils. Both of these are involved in the acute inflammatory response. Activated mast cells and basophils undergo a process called degranulation, during which they release histamine and other inflammatory chemical mediators called (cytokines, interleukins, leukotrienes, and prostaglandins) into the surrounding tissue causing several systemic effects, such as vasodilation, mucous secretion, nerve stimulation, and smooth-muscle contraction. This results in runny nose, itchiness, shortness of breath, and potentially anaphylaxis.
In addition to IgE-mediated responses, egg allergy can manifest as atopic dermatitis, especially in infants and young children. Some will display both, so that a child could react to an oral food challenge with allergic symptoms, followed a day or two later with a flare up of atopic dermatitis and/or gastrointestinal symptoms, including allergic eosinophilic esophagitis. Non-allergic intolerance
Egg whites, which are potentially histamine liberators, also provoke a nonallergic response in some people. In this situation, proteins in egg white directly trigger the release of histamine from mast cells. Because this mechanism is classified as a pharmacological reaction, or "pseudoallergy", the condition is considered a food intolerance instead of a true immunoglobulin E (IgE) based allergic reaction. The response is usually localized, typically in the gastrointestinal tract. Symptoms may include abdominal pain, diarrhea, or any other symptoms typical to histamine release. If sufficiently strong, it can result in an anaphylactoid reaction, which is clinically indistinguishable from true anaphylaxis. Some people with this condition tolerate small quantities of egg whites. They are more often able to tolerate well-cooked eggs, such as found in cake or dried egg-based pasta, than incompletely cooked eggs, such as fried eggs or meringues, or uncooked eggs. Diagnosis
Diagnosis of egg allergy is based on the persons history of allergic reactions, skin prick test (SPT), patch test and measurement of egg-specific serum immunoglobulin E (IgE or sIgE). Confirmation is by double-blind, placebo-controlled food challenges.