Conditions caused by food allergies are classified into three groups according to the mechanism of the allergic response: # IgE-mediated (classic) – the most common type, manifesting as acute changes that occur shortly after eating, and may progress to anaphylaxis # Non-IgE mediated – characterized by an immune response not involving IgE; may occur hours to days after eating, complicating the diagnosis # IgE- and non-IgE-mediated – a hybrid of the above two types Allergic reactions are hyperactive responses of the immune system to generally innocuous substances, such as proteins in the foods we eat. Some proteins trigger allergic reactions while others do not. One theory is resistance to digestion, the thinking being that when largely intact proteins reach the small intestine the white blood cells involved in immune reactions will be activated. The heat of cooking structurally degrades protein molecules, potentially making them less allergenic. Allergic responses can be divided into two phases: an acute response that occurs immediately after exposure to an allergen, which can then either subside or progress into a "late-phase reaction," prolonging the symptoms of a response and resulting 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 (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. Depending on the individual, the allergen, and the mode of introduction, the symptoms can be system-wide (classical anaphylaxis), or localized to particular body systems; asthma is localized to the respiratory system, while eczema is localized to the skin. After the chemical mediators of the acute response subside, late-phase responses can often occur due to the migration of other white blood cells such as neutrophils, lymphocytes, eosinophils, and macrophages to the initial reaction sites. This is usually seen 2–24 hours after the original reaction. Cytokines from mast cells may also play a role in the persistence of long-term effects. Late-phase responses seen in asthma are slightly different from those seen in other allergic responses, although they are still caused by release of mediators from eosinophils. Six major allergenic proteins from cow's<unk>  have been identified: αs1-, αs2-, β-, and κ-casein from casein proteins and α-lactalbumin and β-lactoglobulin from whey proteins. There is some cross-reactivity with soy protein, particularly in non-IgE mediated allergy. Heat can reduce allergenic potential, so dairy ingredients in baked goods may be less likely to trigger a reaction than<unk>  or cheese. For<unk> , non-IgE-mediated responses are more common than IgE-mediated. The former can manifest as atopic dermatitis and gastrointestinal symptoms, especially in infants and young children. Some will display both, so that a child could react to an oral food challenge with respiratory symptoms and hives (skin rash), followed a day or two later with a flare up of atopic dermatitis and gastrointestinal symptoms, including chronic diarrhea, blood in the stools, gastroesophageal reflux disease (GERD), constipation, chronic vomiting and colic.
Milk allergy
Lactose intolerance  Lactose intolerance  1
Egg allergy
Peanut allergy
Corn allergy
Soy allergy
Poultry allergy
Latex allergy