Pharmacotherapy of allergic rhinitis

The pathophysiology, clinical manifestations and diagnosis, and pharmacotherapy of allergic rhinitis are reviewed. Allergic rhinitis is an immunologically mediated disease initiated by an antigen-antibody reaction in sensitized persons. Clinical manifestations include nasal obstruction, rhinorrhea, itching of the nose and eyes, coughing, and sneezing and may be perennial or seasonal. Diagnosis is confirmed by challenging the patient with suspected allergens in skin-prick tests. Avoidance of offending allergens is the cornerstone of therapy. Antihistamines and decongestants provides only minimal relief when used alone and are more effective when combined with other agents. Two newer antihistamines, astemizole and terfenadine, lack the sedative and anticholinergic properties of older antihistamines. Intranasal corticosteroids are particularly effective in relieving symptoms; beclomethasone diproprionate and flunisolide do so without producing systemic adverse effects. Cromolyn sodium is effective in relieving nasal symptoms and is the prototype of a new noncorticosteroidal class of compounds termed antiallergy drugs. Drugs under investigation for the treatment of allergic rhinitis include histamine H2-receptor antagonists, nonsteroidal anti-inflammatory agents, anticholinergic agents, and beta-adrenergic receptor agonists. Immunotherapy is a helpful adjunctive treatment. Treatment with drugs may be necessary for those patients with allergic rhinitis who find it difficult or impossible to avoid the offending allergen. The severity of symptoms and the adverse effects of agents should be considered when individual therapeutic plans are being established.