An allergy is an abnormal reaction by a person’s immune system against a normally harmless substances that we are commonly exposed to.
Allergies can be respiratory (seasonal allergies, allergy to birch or tree pollen, allergy to grass or ragweed, allergies to cats, dogs, dust mites, mold, etc.) and generally trigger rhinitis (nasal congestion, runny nose, sneezing), conjunctivitis (itchy or runny eyes) and/or asthma (coughing, wheezing, shortness of breath and oppression of the chest). Respiratory allergies are different from food allergies (allergy to milk, eggs, soy, peanuts, wheat, nuts, fish, crustaceans, etc.), which can trigger more severe reactions, including anaphylaxis. Not to be overlooked are allergies to vespids (bees and wasps).