Non-allergic rhinitis is defined as a condition causing abundant chronic watery rhinorrhoea which is not allergic in aetiology. It is a general term having a number of conditions, which include Hormonal rhinitis, Vasomotor rhinitis, Occupational rhinitis, Drug-induced rhinitis, Non-allergic rhinitis with eosinophilia syndrome (NARES).Sympathetic stimulation causes construction of blood vessels and shrinkage of mucosa leading to decongestion of nose. Parasympathetic stimulation causes not only excessive secretion from the nasal gland but also vasodilatation and engorgement, which lead to rhinorrhoea and congestion of nose. The autonomic nervous system, which supplies the nasal mucosa, is under the control of hypothalamus. Therefore, emotions play significant role in non-allergic rhinitis.
Prevalence rates of asthma and rhintis symptoms remained quite stable over time. Rates of reported atopic dermatitis symptoms showed an increase over time, but those of diagnosis of eczema did not show a clear pattern. Patients with renal insufficiency, hepatic insufficiency, or both are prone to augmentation of adverse events, resulting from a reduced clearance through renal and/or hepatic pathways. Fortunately, many of the drugs recommended for use in nonallergic rhinitis are administered intranasally. Therefore, subsequent systemic absorption is minimal. Still, antihistamines and some sympathomimetics are administered systemically.