What is an Allergy?
An allergy occurs when your immune system responds aggressively to a harmless environmental substance.
Common inhaled allergens include tree and flower pollen, animal dander, dust, and mold. Ingested allergens include medications (penicillin, for example) and foods such as eggs, peanuts, wheat, tree nuts, and shellfish. Nickel, copper, and latex can also cause allergies.9,10
These allergens can affect various parts of the body and elicit symptoms in the nasal passages (such as itchy, stuffy and/or runny nose, postnasal drip, facial pressure and pain); mouth area (tingling sensation, swollen mouth and lips, itchy throat); eyes (swollen, itchy, red eyes); respiratory (wheezing, coughing, difficulty breathing, shortness of breath); skin (hives, rashes, swelling); and gastrointestinal (stomach cramps, vomiting, diarrhea). Symptoms can occur within minutes to days after exposure and can range from mild to severe.
The most severe form of allergic reaction is called anaphylaxis. It is a potentially deadly condition that results in respiratory distress and swelling of the larynx, often followed by vascular collapse or shock.10 Anaphylaxis should be treated rapidly because death can occur within minutes or hours after the first symptoms appear. Many people prone to anaphylaxis carry self-injecting epinephrine pens in case of emergencies.