ülittundlikkus

Ülittundlikkus, also known as hypersensitivity, refers to an exaggerated or inappropriate immune system response to an otherwise harmless substance or antigen. This response can manifest in a variety of ways, affecting different parts of the body and leading to a wide range of symptoms. The underlying mechanism involves the immune system mistakenly identifying a common environmental factor, such as pollen, certain foods, or animal dander, as a threat.

There are four main types of hypersensitivity reactions, classified by Gell and Coombs. Type I hypersensitivity, often called immediate hypersensitivity or allergy, involves the rapid production of IgE antibodies. Upon re-exposure to the allergen, these antibodies trigger the release of histamine and other mediators, causing symptoms like hives, swelling, and difficulty breathing. Type II hypersensitivity involves antibodies attacking cells or tissues, leading to conditions like autoimmune hemolytic anemia. Type III reactions are immune complex-mediated, where antibodies bind to antigens, forming complexes that can deposit in tissues and cause inflammation, as seen in lupus. Type IV hypersensitivity, or delayed hypersensitivity, is T-cell mediated and typically develops hours or days after exposure, exemplified by contact dermatitis from poison ivy.

Diagnosis of ülittundlikkus often involves a combination of patient history, physical examination, and specific tests such as skin prick tests, blood tests to detect specific antibodies, or patch tests. Management strategies vary depending on the type and severity of the reaction and may include allergen avoidance, medications like antihistamines or corticosteroids, and in some cases, immunotherapy to desensitize the immune system.