1) Autoimmune Response; Celiac Disease: This IgA autoimmune response can cause more than 300 signs and symptoms. Celiac Disease is the most common condition that falls into this category. Basically, there is an autoimmune response to gluten and gliadin which can damage the intestines. Testing for this is done by a Gastroenterologist through blood work and/or small bowel biopsy. I think you should have both. 10-20% of Celiacs test negative on blood work and positive on biopsy. See a gastroenterologist who knows the guidelines for diagnosing Celiac Disease and get tested before going on a gluten free diet! EoE and Celiac Disease and Dermetitis Herpeteformis (DH) are good examples of this and I have Celiac Disease and DH.
2)Food Allergy: Type I immediate IgE hypersensitivity immune response: This reaction typically occurs very quickly (minutes to hours) after eating an offending food; symptoms can be mild or severe. Food allergies can cause anaphylaxis (stopping breathing and death) but they may also experience itchy lips/tongue/throat, stuffy nose, headaches, belly ache, diarrhea, gas, bloating, skin reactions, and sudden fatigue. One mild reaction does not mean the next one will be mild! Testing is typically done through skin tests or IgE blood tests by a doctor/allergist. The majority of food allergies have a quick onset reaction. If sour cream causes immediate diarrhea, or strawberries make your lips swell or peanuts close your throat – you are not going to easily forget that because the symptoms occur so quickly and are severe. IgE food panels can be run to help patients when it’s more difficult to figure out which food is causing their reaction because some may have multiple allergies. IgE testing is run through any standard laboratory and is ordered by a doctor/allergist.
I have an IgE allergy to Milk. I was always told by doctors that I just had a severe lactose intolerance. When I was not getting better following my GF Diet in the 90’s; my GI decided to refer me for food allergy testing. I saw a doctor/allergist and they did skin testing for lots of allergies. When I ingest milk products, pretty quickly, the inside of my ears start to itch, my eyelids swell and I itch all over, followed by severe cramping and pains in my stomach and sometimes I start to sweat and can get irritable. If I have baked cheese or milk, the reaction is much less severe. I am lucky, but this does not mean an anaphylactic reaction will never happen. I know that mild reactions can sometimes become severe. I have a similar reaction to sulfites and nitrates, but more of an itching response. With caffeine it is pretty immediate stomach pain and then sometimes I get hives.
Medications: I have also had immediate reactions to some Medications; Biaxin, Reglan, and Morphine. For example, with Biaxin I had a less severe reaction to Milk (in the form of lactose) that is used to bind the drug together.
These are examples of immediate reactions. The problem with medications is that you often have to call the manufacturer to figure out what is in the medication because they don’t have to label medication like they label food.
3) Non-immediate (delayed) IgG & IgA response; known as a food intolerance or food sensitivity: This is very different from an immediate IgE food allergy response because symptoms may not show up for hours or days; which makes it very difficult to figure out exactly which foods are causing which reaction in the body. Symptoms of IgG food intolerances/sensitivities 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. This is where IgG and IgA food sensitivity testing comes in. Many doctors are not familiar with this type of reaction because it is not always obvious or life threatening and it is harder to diagnose and some delayed IGA reactions can be very serious; such as EoE!
I have minor delayed reactions with Oats, Corn, Quinoa, Millet and Hemp…I have a gluten like reaction to these, or what I would call a “cross reaction”. I did strict elimination diets to figure this out. Blood tests for food sensitivities (IgG) are more likely to be run by functional medicine or non traditional doctors and they are not usually covered by insurance.
We have seen a huge increase in customers with food sensitivities or intolerances and they usually come in and claim a food allergy, it is not the same thing folks! There is some conflicting evidence on the comparison of IgG versus IgE and the testing behind it. Note: being allergic to a food doesn’t mean you are intolerant and being intolerant does not mean you are allergic. IgG testing is often done by alternative practitioners and is said to diagnose inflammatory responses to foods but those tests are not validated by the FDA and therefore this type of testing is often not covered by insurance.
What is the bottom line here? Know the difference between them:
-Celiac Disease: diagnosed via blood tests and endoscopy with intestinal biopsy done by a Gastroenterologist. Dermatitis Herpetiformis: itchy skin rash that is the very specific IgA Skin Manifestation of Celiac Disease, diagnosis is done via skin biopsy by a Dermatologist.