food allergy screening program

Serum specific IgE detection, skin prick test, oral food challenge test； Other items such as food-specific IgG testing and bioresonance allergen testing are highly controversial and are not recommended as routine screening options.

First, let me talk about the specific IgE test that many people have done. To put it bluntly, it is to check the allergic antibodies in your blood against a certain food. Just draw 2ml of venous blood. There is no need to fast. Even if you just took anti-allergic drugs the day before, the results will not be affected. It is also friendly to people with atopic dermatitis and severe allergies. There is no need to stick a needle to contact allergens. But its shortcomings are also obvious: it can only detect IgE-mediated immediate allergy, which is the type that causes rash, wheezing, and swollen mouth within half an hour to a few hours after eating. The kind of delayed reaction that occurs several days after eating, such as eczema, bloating, and constipation, cannot be detected at all. And a positive result can only mean that you are allergic to this food, but it does not mean that you are really allergic - I have seen many people who have been found to have high IgE to mango, but have eaten mango for more than ten years without any problems. This is a typical allergy but not allergic, and there is no need to avoid the food at all.

If you want fast results that can be obtained in 15 minutes, the skin prick test is more suitable and cheap, only tens of dollars. The doctor will drop common food extracts on the inside of your forearm and use a special puncture needle to gently prick the epidermis. There will be no bleeding and no much pain. Just wait for 15 minutes to see if there is any redness, swelling or wheals. But it also has many requirements: you cannot take antihistamines or apply glucocorticoid-containing ointments 3-7 days before the examination, otherwise it will suppress the skin reaction and cause false negatives. If you have severe eczema and your arms are full of ulcerated rashes, you cannot do it. And like serum IgE, it can only detect immediate allergies, and a positive result cannot directly confirm the diagnosis.

So what can be 100% confirmed? It also requires an oral food challenge test, which is also recognized as the gold standard in the global allergy field. The operation is simple: first strictly avoid the food you suspect you are allergic to for 3-4 weeks. After all symptoms have subsided, slowly start eating the food at a small dose, gradually increase the amount, and observe whether there is any allergic reaction. However, please note that if you have experienced severe allergic reactions such as laryngeal edema or shock after eating this food before, you must not try it at home. You must do it at an allergy department with first aid equipment and professional doctors present to avoid danger. There used to be a 3-year-old child who developed a rash after taking a sip of ordinary milk powder. His parents kept giving him deep hydrolysis, and the IgE test also showed that the milk was positive. Later, he did a provocation test at the hospital, starting with 1ml of diluted ordinary milk, and continued to drink 150ml without any reaction. Finally, he switched directly to ordinary milk powder, saving a lot of money.

Having said this, someone will definitely ask, what are the more than 100 food intolerances and the bunch of arrows that I checked before? That is food-specific IgG testing, which is currently the most controversial item in the allergy circle. One school of thought believes that IgG is a sign of food tolerance, not an indicator of allergy. The World Allergy Organization and the Chinese Children's Food Allergy Guidelines have clearly stated that it is not recommended as a routine screening item for food allergy. Many people are found to be positive for rice and wheat, and they will be fine after eating them for a lifetime. If they eat these foods, they will become malnourished. However, some gastroenterologists and pediatricians believe that for patients with long-term unexplained diarrhea, bloody stools, and functional abdominal pain, IgG results can be used as a reference for dietary adjustments. After all, some patients do have relief from their gastrointestinal symptoms after avoiding foods high in IgG. This can only be said that if you simply want to check whether you have food allergies, there is no need to spend this money. If you have digestive tract symptoms that cannot be found for a long time, and you have done other tests, it will be fine. You can refer to it, but don’t treat it as an edict. There is also the bioresonance test that claims to be able to detect hundreds of allergens by holding a metal rod without drawing blood or pricking needles. It has long been labeled as pseudoscience by the State Food and Drug Administration. Just avoid it if you encounter it.

To be honest, I have met too many people who came with a thick stack of test reports and asked, "Beef, mutton, eggs, and milk are all positive, and they are so scared that they dare not eat anything. In fact, it is really unnecessary." All in vitro examinations are auxiliary, and the core still depends on your true reaction after eating the food - if you eat nothing and nothing happens, even if the test result is three plus signs, you should eat when you need to. If you get a rash and can't breathe even after one minute of eating, you must avoid it even if the tests are all negative. Don't lose your mouth and nutrition just for a report. It's a mistake.