delayed allergy
Học thuậtThân thiện
Definition
- Noun:
- An allergic reaction that becomes apparent only hours after contact: A type of hypersensitivity response where symptoms develop and are noticeable a significant time (typically several hours) after exposure to an allergen, in contrast to immediate allergic reactions.
Usage
- The term "delayed allergy" is used in medical and immunological contexts to classify and describe hypersensitivity reactions based on their timing.
- It often refers to reactions mediated by T-cells rather than antibodies, such as contact dermatitis.
Examples
- Noun:
- The rash from poison ivy is a classic example of a delayed allergy, appearing 24 to 48 hours after touching the plant.
- Doctors diagnosed it as a delayed allergy to the metal in her earrings, as the inflammation developed a full day after she wore them.
Advanced Usage
- "Cell-mediated delayed allergy": A more specific term emphasizing that T lymphocytes (a type of white blood cell) are responsible for the slow-onset reaction.
- Contact dermatitis to nickel is a cell-mediated delayed allergy.
Variants and Related Words
- Delayed-type hypersensitivity (DTH) (n): The formal immunological term for a delayed allergy.
- The tuberculin skin test checks for delayed-type hypersensitivity to tuberculosis bacteria.
- Contact dermatitis (n): A common skin condition that is often a manifestation of a delayed allergy.
- Many cases of contact dermatitis are due to a delayed allergy to substances like fragrances or preservatives.
Synonyms
- Delayed hypersensitivity: A direct synonym often used interchangeably in medical literature.
- Type IV hypersensitivity: The technical classification within the Gell and Coombs system of allergic reactions.
Antonyms
- Immediate allergy: An allergic reaction where symptoms appear within minutes of exposure, such as hay fever or anaphylaxis.
- Type I hypersensitivity: The technical classification for immediate, antibody-mediated allergic reactions.
Noun
- an allergic reaction that becomes apparent only hours after contact