The problem with the standard food allergy tests, run by most doctors, allergists, and dermatologists is that they missing out very important food allergy reactions in the testing methods. Most clinics tests for IgE reactions only, which is only found in a small population. Most food allergies are not IgE mediated but are rather IgG reactions or sometimes IgA reactions, such as in celiac disease.
IgE hypersensitivity immune response is commonly known as a food allergy. This reaction typically occurs very quickly (minutes to hours) after eating an offending food and symptoms are generally severe. Many are aware of food allergies causing anaphylaxis (the most common example being peanuts and kids) but they may also experience itchy lips/tongue/throat, stuffy nose, headaches, belly ache, diarrhea, gas, bloating, skin reactions, and sudden fatigue. This test is typically done through the blood or a skin prick test. However most adults have their ‘trigger food’ figured out because the reaction is so quick. If ice cream causes immediate diarrhea, or strawberries create lip swelling, and peanuts close your throat – one does not easily forget. It’s usually fairly obvious because the symptoms occur so quickly to the offending food.
IgG and IgA food allergy response is different from an immediate IgE food allergy response in that symptoms may not show up for hours or days after ingested offending food allergens. This makes it very difficult to pinpoint exactly what foods are causing what reaction in the body especially as people tend to eat the same foods over and over. Symptoms of an IgG and IgA response include: sore throat, stuffy nose, congestion, headaches, belly aches, constipation, diarrhea, gas, bloating, hormone issues, foggy head, headaches, weight gain, fatigue, joint pain, depression, behavior changes, anxiety, and skin issues (particularly acne, eczema, psoriasis). How do you know if dairy products cause your mental fogginess or gluten causes fatigue or almonds increase your acne if you eat them everyday?
Testing for IgG and IgA food allergies is confusing for many healthcare providers as they are not typically trained on these types of reactions as they are neither obvious nor life-threatening. However food allergies, intolerances and sensitivities are gaining public awareness as people are removing offending food groups in order to help support autism/spectrum disorder treatment plans, chronic diseases, and reduce inflammation in the body with success.