Which term refers to the exaggerated immune response to certain antigens in the environment?

Allergy

Allergy is an exaggerated immune response of the body to certain substances in the environment, known as allergens. These allergens can be harmless substances such as pollen, dust mites, animal dander, or certain foods. However, in individuals with allergies, the immune system reacts in an exaggerated manner to these substances.

When a person with allergies is exposed to an allergen, their immune system recognizes it as a threat and triggers an immune response. This immune response involves the production of a type of antibody called immunoglobulin E (IgE). These IgE antibodies bind to mast cells, which are specialized immune cells present in tissues throughout the body.

Upon subsequent exposure to the same allergen, the allergen binds to the IgE antibodies on mast cells, leading to the release of various chemicals, including histamine and serotonin. These chemicals cause inflammation and other symptoms associated with allergies, such as sneezing, itching, watery eyes, runny nose, and difficulty in breathing.

The symptoms of allergies can range from mild to severe, depending on the individual and the specific allergen. Common allergic conditions include hay fever (allergic rhinitis), asthma, eczema, and food allergies.

To diagnose allergies, doctors may perform allergy tests, such as skin prick tests or blood tests, to identify specific allergens that trigger an immune response in an individual. Treatment for allergies often involves avoiding the allergen whenever possible and managing symptoms with medications such as antihistamines, nasal sprays, and in severe cases, immunotherapy (allergy shots).

It's important to note that allergies are different from autoimmunity, which is a condition where the immune system mistakenly attacks the body's own cells and tissues. In allergies, the immune response is directed against harmless substances in the environment, whereas in autoimmunity, the immune system targets the body's own cells as if they were foreign.