Allergic rhinitis is one of the most common allergic diseases affecting in the region of 20% . It is the inflammation of the inside of the nose resulting from a reaction to an airborne allergen such as dust or pollen. Rhinitis manifests itself as a blocked or runny nose, sneezing and itchiness which is often difficult to distinguish from a common cold.
Finding the exact cause of your allergic rhinitis may be straightforward or require some detective work to identify the trigger. Perhaps the biggest clue to what might be causing your allergy is whether it only occurs at certain times of year or not.
Rhinitis that only affects sufferers at a particular time of year is referred to as seasonal allergic rhinitis. It is also known as hay fever on account of grass pollen being the most common allergen to set off the symptoms. Grass pollen is released between May and July (in the U.S and Europe) but there are many other types of pollen that also cause hay fever. Depending on the time of year the allergy is most noticeable it may be possible to identify the plant. For example weed pollen tends is released from June to September whereas mold spores peak from September to October.
Unfortunately it is not unheard of for a person to be allergic to more than one pollen type resulting in an extended allergy season.
If symptoms occur year round then the condition is described as perennial allergic rhinitis and this is most likely caused by indoor allergens such as house dust mites, pet dander or indoor molds.