Currently, there are various methods of allergen screening, but the following four allergy screening methods are recognized by domestic and foreign authorities and proven to be meaningful in practice, parents should look carefully: 1. Look at the results after 15-20 minutes. If the skin surface appears with an itching sensation, congratulations, you may be allergic to the substance. The advantage of the test is that it is quick and the results are reported immediately. Before the test, you need to stop using oral anti-allergy drugs for more than 3-7 days. 2, allergen in vitro testing: only a tube of blood is needed to take a food-specific IgE (not IgG) test to determine the substance that causes your allergy. Common food allergens such as eggs, milk, shrimp and crab, and inhalant allergens such as dust mites, mold, cat hair and dog hair, pollen, etc. can be accurately detected by the instrument. In vitro blood testing does not require discontinuation of anti-allergy medication, fasting, and no age limit. 3, stimulation test: there are food stimulation, nasal stimulation, bronchial stimulation test, etc. Take food stimulation as an example, that is, let you eat something that may cause allergy, starting from a small amount, gradually increasing to a certain amount, and observe whether there are allergic symptoms in the process of increasing the amount. If you are not sure of the degree of allergy, food stimulation test is very risky, so the whole process must be carried out under the supervision of a professional doctor, do not try at home Oh. 4, patch test: is the daily life and various occupations often contact and may cause allergic substances prepared into a commercialized (standardized) patch reagent, will be applied to the back, 2-3 days later to observe the skin reaction. The patch test is currently the simplest and most accurate method for diagnosing contact skin allergic reactions.