Hay fever, allergic rhinitis or pollenosis is an allergic inflammation of the nasal airways. In Western countries between 10—25% of people annually are affected by allergic rhinitis.
It occurs when an allergen such as pollen or dust is inhaled by an individual with a sensitized immune system, and triggers antibody production.
These antibodies mostly bind to mast cells, which contain histamine. When the mast cells are stimulated by pollen and dust, histamine (and other chemicals) are released. This causes itching, swelling, and mucus production.
Symptoms vary in severity between individuals.
Very sensitive individuals can experience hives or other rashes. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate the condition.
The two categories of hay fever / allergic rhinitis include:
- Seasonal – occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age.
- Perennial – occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.
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Last Updated: Sep 16, 2014