Posted by Leo Wang on 11th Apr 2014
Allergic rhinitis is 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.
Allergic rhinitis may be seasonal or perennial. Seasonal allergic rhinitis occurs particularly during pollen seasons. It does not usually develop until after 6 years of age. Perennial allergic rhinitis occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.
The characteristic symptoms of allergic rhinitis are: rhinorrhea (excess nasal secretion), itching, and nasal congestion and obstruction.
Characteristic physical findings include conjunctival swelling and erythema, eyelid swelling, lower eyelid venous stasis, transverse nasal crease, swollen nasal turbinates, and middle ear effusion.
Sufferers might also find that cross-reactivity occurs. For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes. A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food. There are many cross-reacting substances.
Allergic rhinitis triggered by the pollens of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during haying season. However, it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies between individuals and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated plants are the predominant cause.