Owing to the length of treatment, which should not be less than 3 years, immunotherapy is best used in patients whose symptoms are inadequately controlled in spite of appropriate environmental measures and symptomatic therapy. It is a condition of unknown origin associated with altered vasomotor control in the nasal mucous membrane resulting in chronic nasal congestion. Numerous non-specific stimuli such as changes in ambient temperature, odours, fumes, medications, humidity, changes in barometric pressure and emotional stimuli can trigger nasal obstruction and rhinorrhoea. Vasomotor rhinitis is rather common and often co-exists with allergic rhinitis. The diagnostic procedures are directed towards excluding allergic causes for the nasal congestion.
Therapy is less successful than for allergic rhinitis.
Infectious Rhinitis Viral upper respiratory infections are frequent causes of rhinitis. The common cold is characterised initially by sneezing and watery rhinorrhoea. Within a few days the nasal discharge becomes purulent, with a predominance of neutrophils noted in nasal smear. The nasal mucous membrane is erythematous. The allergic patient with infection often has more intense and intractable symptoms than do those who are not allergic.