How do allergies function in immune system responses?

Allergies occur when the immune system overreacts to harmless substances, triggering an immune response.

When a person with allergies comes into contact with an allergen, such as pollen or pet dander, their immune system mistakes it for a harmful invader and produces an antibody called immunoglobulin E (IgE). These antibodies bind to mast cells and basophils, which are immune cells that release histamine and other chemicals in response to an allergen. This causes inflammation, swelling, and other allergy symptoms.

Allergies can be classified as either immediate or delayed hypersensitivity reactions. Immediate hypersensitivity reactions occur within minutes of exposure to an allergen and can cause symptoms such as hives, itching, and anaphylaxis. Delayed hypersensitivity reactions occur hours to days after exposure and can cause symptoms such as eczema and contact dermatitis.

Treatment for allergies typically involves avoiding the allergen and taking medications such as antihistamines, corticosteroids, and decongestants to relieve symptoms. In severe cases, immunotherapy may be recommended, which involves gradually exposing the person to increasing amounts of the allergen to desensitize their immune system.

Overall, allergies are a result of the immune system's attempt to protect the body from harmful invaders, but in the case of allergies, the immune system overreacts to harmless substances.