An allergy is a hypersensitivity reaction of the immune system to a specific substance, called an allergen. When the body comes into contact with the allergen, it activates the immune system to produce antibodies called immunoglobulin E (IgE). These antibodies trigger the release of chemicals, such as histamine, which cause inflammation and other symptoms.
Allergies can affect different parts of the body, including the nose, lungs, skin, and digestive system. Common allergens include pollen, mold, dust mites, animal dander, food, and medications. Symptoms of an allergy may include sneezing, runny nose, itchy eyes, coughing, shortness of breath, hives, rash, or swelling. Some allergies can cause a severe allergic reaction, known as anaphylaxis, which can be life-threatening and requires immediate medical attention
What are the Most Common types of Allergies
Common Signs and Symptoms of Allergies