Allergic rhinitis is a common medical condition, and numerous pharmacologic agents are available for the management of symptoms. Because many of the medications used to treat allergic rhinitis are available over-the-counter (OTC), patients frequently attempt treatment without consulting a physician. As a result, many of those who do visit a doctor have already experienced treatment failure. Because the various treatment options may overlap or complement one another, the development of an effective treatment plan requires a thoughtful appraisal of the patient's symptoms.
In the April 2005 issue of The Journal of Respiratory Diseases, I reviewed the use of antihistamines, decongestants, and cromolyn for the management of allergic rhinitis. In this article, I will focus on intransasal corticosteroids, leukotriene modifiers, and combination therapy. I will also discuss immunotherapy and patient education.Intranasal corticosteroids
Since corticosteroids have broad anti-inflammatory and immunosuppressant activity, they are effective as monotherapy for allergic rhinitis when applied topically (Table 1). The anti-inflammatory potential of corticosteroid therapy was demonstrated in a nasal cytology study of patients with allergic rhinitis who were treated with intranasal fluticasone(Drug information on fluticasone).1 The proportion of patients with nasal eosinophils and basophilic cells significantly decreased after fluticasone treatment.
One 8-week clinical trial compared fluticasone aqueous nasal spray, budesonide(Drug information on budesonide) in a reservoir powder device, and placebo.2 In weeks 1 to 4, fluticasone effectively lowered total nasal symptom scores, compared with budesonide and placebo, at all time points. Over weeks 1 to 8, it effectively lowered individual scores for sneezing and itching, compared with budesonide, and lowered all individual symptom scores, compared with placebo.2
Most of the symptoms associated with seasonal allergic rhinitis, including nasal obstruction, rhinorrhea, sneezing, and nasal itching, respond to intranasal corticosteroids administered once or twice daily.3 In comparison trials, intranasal corticosteroids were significantly more effective than cromolyn in relieving symptoms of allergic rhinitis.4 Once-daily use of an intranasal corticosteroid has also been shown to be more effective than use of an oral antihistamine in reducing symptoms of seasonal allergic rhinitis and improving quality of life.5,6
A meta-analysis of 9 randomized, controlled, single- or double-blind studies involving 648 patients with allergic rhinitis indicated that total nasal symptom scores were reduced significantly more for those who received intranasal corticosteroids than for those who received oral antihistamines.7 Overall reductions in total individual symptom scores for sneezing, rhinorrhea, itching, and nasal blockage were also significantly greater with intranasal corticosteroids; however, for all symptoms except nasal blockage, individual results varied substantially among the trials.7
While corticosteroids are clearly effective, one study found that at least 50% of patients with allergic rhinitis who were treated with fluticasone still needed to take an antihistamine for adequate control of symptoms.8 In addition, achieving relief of symptoms with intranasal corticosteroids may take several days, and sustaining this relief requires long-term administration.
Corticosteroids can have a prophylactic effect when given to patients with seasonal allergic rhinitis before the start of an allergy season. In a randomized study, intranasal triamcinolone(Drug information on triamcinolone) acetonide administered preseasonally was found to prevent nasal symptoms and reduce the severity of subsequent symptoms in patients with allergic rhinitis.9 Patients received triamcinolone once daily for 6 weeks; treatment was started at least 1 week before significant ragweed pollen was detected.
Intranasal corticosteroids are generally safe; they have few systemic adverse effects and few effects on plasma cortisol levels.10 However, in 2000, aqueous beclomethasone nasal spray was reported to cause growth inhibition in children.11 A 1-year study of 100 prepubertal children who had perennial allergic rhinitis indicated that those treated with aqueous beclomethasone, 168 µg twice daily, had a significantly lower over- all growth rate than did placebo-treated children.11
However, subsequent studies and several published analyses of the relevant literature indicate that intranasal corticosteroids, used in prescribed doses, are not associated with restricted skeletal growth in children.12-16 Because some children may be particularly at risk, careful attention to height measurements should be maintained throughout therapy.Leukotriene antagonists
The recognized role of cysteinyl leukotrienes (CysLT) in the pathophysiology of allergic and inflammatory diseases provides a rationale for the use of leukotriene antagonists in the treatment of allergic rhinitis. Leukotrienes released during the allergic response play a role in chemotaxis, and they increase vascular permeability in the nose. Key synthetic and signaling proteins of the CysLT pathway have been identified in eosinophils and mast cells recovered from nasal washes of patients who have active seasonal allergic rhinitis.17
The efficacy of oral leukotriene antagonists in the treatment of allergic rhinitis has been confirmed in clinical trials. In a study of more than 1300 adults with active allergic rhinitis symptoms, montelukast(Drug information on montelukast), administered once daily at bedtime for 2 weeks, significantly improved daytime nasal symptoms and quality-of-life scores; montelukast was comparable in efficacy to once-daily loratadine(Drug information on loratadine).18 Leukotriene receptor antagonists have also been reported to improve quality of life significantly, when compared with placebo, in patients with rhinoconjunctivitis.18,19
However, a meta-analysis of randomized controlled trials, which included 11 studies of seasonal allergic rhinitis, found that leukotriene receptor antagonists, while effective, were outperformed by antihistamines and intranasal corticosteroids.19 Although leukotriene receptor antagonists reduced mean daily symptom scores compared with placebo, antihistamines reduced those scores by an additional 2%, and intranasal corticosteroids produced reductions that were 12% greater still. In general, leukotriene modifiers may be most appropriate for patients who would prefer not to take corticosteroids.