Skin allergy patients need to carry out routine blood tests, allergen testing and so on. 1. Routine blood test: some patients with skin allergy may have elevated eosinophils in the routine blood test, in addition to infection-induced urticaria and other allergic diseases may have elevated white blood cells. 2. Allergen testing: patients with skin allergies can also undergo skin prick test, patch test, intradermal test, etc. to clarify the allergens. There are many causes of skin allergy, but the trigger is often difficult to trace. It is recommended to go to the hospital in time after the skin allergy, complete the relevant examination under the guidance of the doctor, and carry out the appropriate treatment.