How to detect food allergens

At present, food allergen testing in regular hospitals is mainly divided into two categories: in vivo and in vitro. If you suspect that you are allergic to food, do not buy self-test products online. First, go to the allergy department (also known as the allergy department) to register. The doctor will choose the appropriate testing method based on your symptoms. This is the most worry-free and most accurate way.

I just met a girl in her 20s two weeks ago. After eating crayfish several times, the corners of her mouth became red and she developed a rash. The Internet celebrity allergen package I tested at home said that she was allergic to shrimp, crab, beef, and oranges. She was so scared that she only dared to eat vegetables with rice for half a month. When she came to the doctor, her face was sallow. We did a skin prick and serum-specific IgE test on her, and the results showed that she was actually only allergic to the specific protein in crayfish and shrimp roe. Crab and beef were completely fine. The previous self-test results were ridiculously wrong.

Speaking of this, I have to mention that the most common pitfall for everyone now is to confuse food IgG testing and allergen testing. At present, there are still differences in the academic circles on the reference value of IgG testing. One group believes that this is just the normal immune memory of the body after contact with food. It has nothing to do with allergies at all. Taking the test is equivalent to a white test. ； The other group believes that if it is chronic diarrhea, recurring eczema, or migraines that have no cause for a long time, the IgG results can be used as clues for investigation, but you must not rely on this result alone to directly avoid food, especially for children who are still growing. Blind taboos can easily lead to developmental delays.

If the conventional prick and serum test results do not match your actual reaction, doctors will generally recommend a food challenge test, which is currently recognized as the gold standard for allergen testing. Under the full supervision of medical staff, you will gradually eat the food you are allergic to, starting from a very small dose, and monitor your blood pressure, skin, and respiratory tract reactions in real time. Last time, a parent brought his 5-year-old baby here. The previous test report stated that he was severely allergic to milk. During the provocation test, he started eating biscuits with a little milk, and finally drank half a cup of pure milk without any reaction. In fact, he had acute enteritis when he was a child. He drank milk during that time, so the parents mistakenly thought it was an allergy, and the baby was deprived of milk for three years.

By the way, remember to stop all antihistamine allergy drugs one week before the test, such as loratadine and cetirizine. Otherwise, the allergic reaction of the skin will be suppressed, and the results will be false negatives, which is equivalent to wasting money. There are also some people who have hidden allergies that cannot be detected by any instrument. In this case, they should keep a food diary for 1-2 months, including what they ate at each meal and whether they felt uncomfortable in the next few hours. Slowly checking can be more accurate than high-end tests.

Don’t treat the test results as a lifelong “no-no list”. Allergies themselves are the result of dynamic changes in immune status. Foods you were allergic to when you were a child may be tolerated as your immunity changes as you grow older. Just recheck once a year or two. Don’t be too anxious.