What items to check for food allergy

At present, food allergy-related examinations carried out routinely in clinical practice are mainly divided into internal and external types. It is not necessary to do a full set of tests. The doctor will generally ask about the pattern of your allergic attacks and the severity of your symptoms before choosing the most appropriate item.

A while ago, the mother of a boy who just entered elementary school came to us and said that every time his child ate peaches, the area around his mouth would turn red and he would always rub his eyes. Before, he always thought it was peach hair pricks. When he came, we did a skin prick test and the results came out in 15 minutes. It was indeed positive for peach allergens, and it was clear without even drawing blood. Don’t underestimate this prick test. It involves dropping a small amount of common food allergen extracts on the skin of your forearm, and gently rubbing the surface with a special small needle. There is no pain at all. The price is low and the results are quick. It is very suitable for people who clearly suspect that certain types of food trigger acute allergies. The only thing to note is that you must stop taking antihistamine anti-allergic drugs 3 days before the test, otherwise it is easy to get false negative results.

If your allergic symptoms have been on and off for several months, and you are not sure what you ate each time you have an attack, or you have severe eczema on your skin, and it is easy to have a false positive reaction after pricking, then it is more suitable to draw venous blood to test food-specific IgE. This test is not affected by medication and skin condition, and can cover dozens of common allergenic foods such as milk, eggs, nuts, seafood, etc. at once. However, the results have to wait two or three days, and the cost is higher than pricking.

It should be mentioned here that food-specific IgG testing is much discussed now. There are indeed differences in the clinical value of the food-specific IgG test. Some scholars believe that this indicator can only reflect the human body’s exposure to such foods and cannot be used as a basis for diagnosing allergies. If there are no symptoms and only high IgG levels are used, blindly avoid foods, which may easily lead to nutritional imbalance.； Some clinicians also believe that it has certain reference significance for chronic and recurring unexplained allergies. Our current treatment principle is that we will not use the IgG results alone to make a diagnosis, but will definitely make a comprehensive judgment based on your actual reaction after eating the corresponding food.

If the results of the previous two tests are ambiguous, and it is really impossible to determine the allergen, there is another "gold standard" for diagnosis, which is the oral food challenge test. In the case where the hospital has emergency equipment and doctors monitor the entire process, the intake of suspected allergenic foods is gradually increased from a very small amount to observe whether there is an allergic reaction. The results are the most accurate, but there is a certain risk of inducing severe allergies, so it will only be arranged when necessary.

By the way, don’t trust the fingertip blood-based home allergen kits sold online for tens of dollars. A little girl was diagnosed with more than 20 food allergies at home. She was so scared that she didn’t dare to touch rice or noodles for half a year. When she came to see me for a consultation, she didn’t feel any discomfort after eating those so-called “allergens.” The accuracy of such household kits is not guaranteed at all. If you really doubt that you have a food allergy, go to a regular hospital for a checkup. Don’t scare yourself, as eating too little will harm your body.