What is an allergy? An allergy is an abnormal reaction from an immune response to something that comes in contact of skin or inhaled, or ingested in body. Allergic reactions can lead to sneezing, wheezing, coughing, itching, skin rashes, swollen face or tongue, stomach pain, diarrhea etc. Why is skin-testing for allergies done? Skin-testing is a method that doctors use to see whether a patient’s exposure to specific substances provokes an allergic response. Extracts (i.e. material used for allergy testing) are made from common allergens like various plant source (e.g. grass, trees, and pollen); mold spores; animal dander; cockroach or...