Non-immunoglobulin E-mediated food allergy
and
Food-related pseudoallergies without IgE-mediated response

"Non-immunoglobulin" can refer to two main concepts: small, single-domain proteins used as alternatives to antibodies, or non-IgE-mediated food allergies, a type of food hypersensitivity that often presents with gastrointestinal symptoms.

Food-related pseudoallergies are caused by natural or artificial substances in food and liquids, including tap water, that trigger symptoms without an IgE-mediated response. These are some of the food additives currently recognized, but several others are not. 


While true allergies involve an IgE-mediated immune response, pseudoallergies are a direct pharmacological effect or cause mast cells to release inflammatory mediators without antibody involvement.These reactions are often caused by food additives (like sulfites or certain colorings) or naturally occurring compounds in foods (such as histamine, salicylates, or tyramine).


How does it differ from a true allergy

• True allergy: Triggered by the immune system mistakenly identifying a food protein as a threat. It involves a specific immune response mediated by IgE antibodies.

• Pseudoallergy: Triggered by direct exposure to a chemical substance or a lack of an enzyme to break down a substance. It does not involve IgE antibodies, but can still cause mast cells to release histamine and other mediators, leading to an inflammatory reaction. 

• Gastrointestinal issues: bloating, nausea, diarrhea, abdominal pain
• Respiratory symptoms: choking, shortness of breath, stuffy nose
• Skin reactions: flushing, hives, itching, and several other skin reactions.
• Headache, migraine
• Low blood pressure
• Fatigue
• anaphylactoid symptoms.
• Angioedema

Common Food Pseudoallergens and Triggers

Naturally Occurring Substances (Biogenic Amines, Salicylates, etc.):

Histamine: Found in aged, fermented, or spoiled foods, histamine can trigger a reaction when the body's enzyme (diamine oxidase or DAO) is unable to break it down efficiently.

High-histamine foods: Aged cheeses, wine, beer, cured/smoked meats (salami, bacon), certain fish (tuna, mackerel, anchovies), fermented foods (sauerkraut, yogurt, soy sauce), spinach, tomatoes, and eggplant.

Histamine liberators: Some foods can trigger the direct release of the body's own histamine from mast cells. Examples include blueberries, strawberries, citrus fruits, pineapple, papaya, nuts, and egg whites.

Tyramine and other vasoactive amines: These are also biogenic amines found in foods like cheese, wine, nuts, and fermented sausages, and can cause migraines and nausea.

Salicylates: Aspirin-like compounds are naturally present in many fruits, vegetables, herbs, and spices.

High-salicylate foods: Berries, apricots, cherries, oranges, pineapple, tomatoes, peppers, curry powder, paprika, and mint.

Other natural compounds: Certain fruits and vegetables, such as apples, peaches, celery, and spinach, may also trigger symptoms in some individuals. 

Food Additives:
Reactions to food additives are a common form of pseudoallergy. 

Preservatives:

Sulfites (E220–E227): Used in dried fruits, canned goods, wine, and processed meats. They can trigger asthma attacks.

Benzoates (E210–E219): Found in soft drinks, juices, pickles, and some fruits like prunes.

Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT): Antioxidants used to prevent fats from becoming rancid; can cause hives and asthma.

Colorings:

Tartrazine (Yellow dye #5, E102): A yellow dye used in beverages, candy, and some canned vegetables, known to cause hives and asthma in some people.

Carmine (natural red 4): A red coloring agent that can cause facial swelling, angioedema, hives, and wheezing.

Flavor Enhancers/Sweeteners:
Monosodium glutamate (MSG, E621): May trigger the "Chinese Restaurant Syndrome," which causes burning and tightening of the chest/face.

Aspartame: An artificial sweetener that can cause hives or headaches.