Allergic rhinitis the allergen. Intranasal corticosteroids are the preferred medical treatment for persistent symptoms, with other options if this is not effective. Second line therapies include antihistamines, decongestants, cromolyn, leukotriene receptor antagonists, and nasal irrigation. Antihistamines by mouth are suitable for occasional use with mild intermittent symptoms. Mite-proof covers, air filters, and withholding certain foods in childhood do not have evidence supporting their effectiveness. Antihistamine drugs can be taken orally and nasally to control symptoms such as sneezing, rhinorrhea, itching, and conjunctivitis. It is best to take oral antihistamine medication before exposure, especially for seasonal allergic rhinitis. In the case of nasal
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