Allergic rhinitisis an allergic inflammation of the nasal airways. It occurs when an allergen, such as pollen, dust, or animal dander (particles of shed skin and hair) is inhaled by an individual with a sensitized immune system.
In such individuals, the allergen triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils containing histamine. When caused by pollens of any plants, it is called pollinosis, and, if specifically caused by grass or tree pollens, it is known as hay fever. While symptoms resembling a cold or flu can be produced by an allergic reaction to pollen from plants and grasses it does not cause a fever. The link with hay came about due to an early (and incorrect) theory that the symptoms were brought about by the smell of new hay (coumarin). A competing popular name was ‘hay asthma’.
In such individuals, the allergen triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils containing histamine. When caused by pollens of any plants, it is called pollinosis, and, if specifically caused by grass or tree pollens, it is known as hay fever. While symptoms resembling a cold or flu can be produced by an allergic reaction to pollen from plants and grasses it does not cause a fever. The link with hay came about due to an early (and incorrect) theory that the symptoms were brought about by the smell of new hay (coumarin). A competing popular name was ‘hay asthma’.