In daily life, many people develop allergic skin diseases such as hives and eczema, which need to be checked and the allergens need to be detected before they can be treated in order to achieve a good cure. So the following we will learn about the common allergen detection methods. 1, intradermal test: intradermal injection of allergens, after a certain period of time to observe the skin reaction, according to the skin reaction to determine whether the allergy to this allergen. 2, prick test: prick test can be regarded as a special intradermal test, the method is first prick skin test solution drops on the skin, and then use a prick needle through the drops, prick into the skin. The skin puncture solution is only one ten-thousandth of the intradermal test, which is safer. Due to the small skin lesions, the patient is painless. a. Inhalant allergens include mites, molds, Artemisia, elm and poplar, animal fur, pollen, etc. b. Food allergens include fish, shrimp, crab, pork, beef and mutton, milk, eggs, beans, peanuts, spices, etc. All 30 minutes for the results. Principle: When a certain allergen enters the skin, patients who have a rapid allergic reaction to certain substances immediately and specifically cause degranulation of mast cells in the skin, releasing histamine and other active substances, resulting in local capillary dilation (erythema) and increased capillary permeability (edema, wind mass), and those who are positive indicate allergy to the antigen. Operation method: first put a drop of puncture skin test solution on the skin, and then use a puncture needle to pass through the drop and gently pierce into the skin. 3, patch test: patch test is mainly used for the examination of contact dermatitis. Method: After the reagent is applied to the skin and observed for a period of time, the skin’s reaction to the contact is used to determine whether it is allergic to the substance. European standardized patch reagent is used for accurate testing. It includes allergens of hundreds of sub-categories in twenty categories, such as drugs, rubber products, skin care products, preservatives, toys, home furnishing materials, hair dyes, printing materials, textile dyes, bleaching agents, metal jewelry, spices and other industrial and agricultural and daily chemical products. The principle is that the suspected allergenic substance is applied to the patient’s skin, and the antigen is presented to the T lymphocytes by the antigen presenting cells after entering the body through the skin or mucous membrane, which activates the specific T lymphocytes and induces an inflammatory reaction. Through the above, we should have a basic understanding of how to check allergens, and hope that we must go to the regular hospital to do the above examination to identify the specific allergens to do the right treatment, and patients should also pay attention to avoid contact with allergens in the future to prevent the recurrence of the disease.