Allergies are a hypersensitive immune response to substances that are normally harmless to most people. These substances, known as allergens, can trigger an immune reaction in individuals who are sensitive or allergic to them. Common allergens include pollen, dust mites, pet dander, certain foods (such as nuts, shellfish, dairy), insect stings, and certain medications.
When an allergic person is exposed to an allergen, their immune system reacts by producing antibodies called immunoglobulin E (IgE). These antibodies bind to mast cells and basophils, which are types of immune cells found in various tissues throughout the body. Upon subsequent exposure to the allergen, these cells release histamine and other chemicals, leading to the symptoms associated with allergies.
Allergy symptoms can vary widely depending on the allergen and the individual’s sensitivity. Common symptoms include sneezing, runny or stuffy nose, itchy or watery eyes, skin rashes or hives, swelling, difficulty breathing, and in severe cases, anaphylaxis, which is a life-threatening allergic reaction that requires immediate medical attention.
Treatment for allergies typically involves avoiding exposure to allergens whenever possible and using medications such as antihistamines, decongestants, nasal corticosteroids, and allergy shots (immunotherapy) to alleviate symptoms and reduce the immune system’s sensitivity to the allergen over time.