Allergic rhinitis region to region; in general, the tiny, hardly visible pollens of wind-pollinated plants are the predominant cause. Pollens of insect-pollinated plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include: Allergic rhinitis may also be caused by allergy to Balsam of Peru, which is in various fragrances and other products. Allergy testing may reveal the specific allergens to which an individual is sensitive. Skin testing is the most common method of allergy testing. This may include a patch test to determine if a particular substance is causing the rhinitis, or
Rhinitis to as "mixed rhinitis". The pathology of vasomotor rhinitis appears to involve neurogenic inflammation and is as yet not very well understood. The role of transient receptor potential ion channels on the non-neuronal nasal epithelial cells has also been suggested. Overexpression of these receptors have influence the nasal airway hyper-responsiveness to non-allergic irritant environmental stimuli (e.g., extremes of temperature, changes in osmotic or barometric pressure). Vasomotor rhinitis appears to be significantly more common in women than men, leading some researchers to believe that hormone imbalance plays a role. In general, age of onset occurs after 20 years of age, in