Different allergens can settle on your skin enter into your body system, making your body overreact to the simulative responses. When the human body overreacts with the help of simulation, it is termed an allergy. Allergy can be detected through allergy tests. It acts as a recognizing factor to detect whether the body is allergic to the specific type of substance or not. The most general causes of allergy are allergens which are further classified into three types. The initial one is inhaled allergens, the next one is ingested allergens and the final one is contact allergens. An allergy test can be of two types. The initial one is a blood test and the other one is a patch test. In the blood test, a blood sample is tested for different allergies. And in patch tests, the portion of the skin is tested for allergies.