Allergic rhinitis is a common
chronic condition that is characterized by
inflammation of the nasal mucosa. Although
allergic rhinitis is a condition with upper respiratory symptoms, there is a growing body of evidence to suggest that
allergic rhinitis may be linked to the development of systemic allergic manifestations that include allergic
asthma. The evidence reveals that individuals with
allergic rhinitis are sensitized to the eliciting
allergens and exhibit cutaneous and
respiratory hypersensitivity responses on exposure to the
allergen. On exposure to a nasal
allergen, circulating
immunoglobulin E levels increased and remained elevated 2 weeks after the initial provocation. Patients with
allergic rhinitis exhibit peripheral
eosinophilia and basophilia, the magnitude of which correlates with the severity of symptoms. Additionally, there are several links between
allergic rhinitis and
asthma. First, 85% to 95% of patients with allergic
asthma report
rhinitis symptoms, and the severity of the 2 conditions increases in parallel on exposure to an
allergen. Second,
nasal administration of
allergens can provoke impaired lower airway airflow in 25% to 30% of individuals and cause airway
eosinophilia, as evidenced by increased numbers of eosinophils in sputum and mucosal biopsy specimens. Third, the treatment of
seasonal allergic rhinitis with both systemic (eg,
antihistamines) and local agents (eg, glucocorticosteroid analogues) can alleviate the symptoms of
asthma. In summary, evidence that associates
allergic rhinitis with systemic immunologic and inflammatory processes is growing, thereby warranting further in-depth investigation.