(A) Examination of rapid-onset allergic reactions ~ prick test 1. Prick test should not be performed to detect allergens during the acute period, which is prone to false-positive results. 2. Allergen testing should be avoided during drug administration, which is prone to false-negative results. Generally, antihistamines are discontinued for 3 days and above (also considered short-acting and intermediate-acting for 72 hours, and long-acting such as astemizole requires more than 3 weeks.) Hormonal drugs discontinued for 1 week and above is optimal (it is also considered that there is no effect). 3, allergen test does not find allergic substances and does not exclude that the patient has allergens. 4.Allergens tested positive for allergens are not set in stone. 5.Allergic reactions have both rapid and delayed forms, so it is best to observe the results for a longer period of time when testing for allergens to prevent delayed allergic reactions. 6. Positive skin scratching is not advisable 7. It can be started from the age of 1 year, usually from the age of 4 to 5 years. In addition, it is not appropriate during pregnancy. 8.Not suitable for receiving β-blocker and ACE inhibitor therapy. (B) Examination of delayed allergic reactions ~ patch test 1. Patients in the acute phase of contact dermatitis are not suitable for patch test. 2, if the patient is undergoing anti-allergic treatment, the test needs to be stopped after discontinuation: patients taking oral glucocorticoids (such as prednisone, methylprednisone, dexamethasone or trenbolone, etc.) need to stop using them for 2 weeks; patients taking antihistamines need to stop taking them for 3 days. 3. Patients taking oral immunosuppressants (including herbal medicines such as tretinoin preparations) also need to stop taking them for 2 weeks. 4.For patients treated with physical methods such as phototherapy and radiotherapy, they need to stop treatment for 4 weeks before conducting the patch test. 5.During the patch test, patients should avoid sweating and prevent sun exposure, and if the allergic reaction at the patch location is serious, it should be removed in time to stop the test. 6. Not recommended during pregnancy, breastfeeding and infancy.