What is the purpose of exposing or injecting a patient with very small doses of possible allergens in determining the cause of an allergy?

Step-by-step solution

The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The substances to which such an immune response is produced are called allergens. By exposing or injecting a patient with very small doses of possible allergens, the cause of an allergy can be determined by studying the reactions. The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The substances to which such an immune response is produced are c