Allergic rhinitis is a significant health care problem, affecting 20% of the population in the United States.1 It ranks as the sixth most prevalent chronic illness, accounting for more than 11 million office visits and more than $2 billion in costs annually.1 Numerous conditions associated with allergic rhinitis, including asthma, sinusitis, otitis, and nasal polyps, probably boost costs to upward of $10 billion per year.
Clearly, allergic rhinitis is not a trivial disease. Aside from the aforementioned medical conditions, allergic rhinitis can have a profound impact on quality of life. For example, children with allergic rhinitis may have trouble learning or may suffer from irritability and sleep disturbances. Approximately half of patients with allergic rhinitis have symptoms for more than 4 months of the year, and 20% have symptoms for more than 9 months.1
The most significant comorbidity associated with allergic rhinitis is bronchial asthma, occurring in more than 40% of patients with allergic rhinitis.2 This association, or "linkage," between the upper and lower airways has been recognized for decades. However, for a number of reasons, an artificial distinction between treating concomitant allergic rhinitis and asthma has developed. This has occurred despite much information linking the two diseases both immunologically and pathophysiologically.
This article presents recent information on treating allergic rhinitis in both the upper and the lower airways. Topical nasal steroids and their effects on the lower airway are also discussed.
ALLERGIC INFLAMMATION AND "ALLERGIC RHINOBRONCHITIS"
A recent article by Simons3 reviewed how similar allergic rhinitis and bronchial asthma are. Aside from the similarities in their epidemiologies, similarities have also been noted in their immunopathology and pathophysiology mechanisms.
Immunologically, a type I, IgE-mediated reaction initiates both allergic rhinitis and asthma. This is followed by a persistent inflammatory response involving macrophages (Langerhans' cells), CD4+ (Th2-type helper cells), eosinophils, and cytokines IL-4, IL-5, and IL-13, and other mediators (histamine and platelet-activity factor). Clinically, this results in chronic nasal congestion and persistent inflammation associated with bronchial hyperreactivity and airway remodeling in the lungs. In calling this inflammatory change "allergic rhinobronchitis," Simons linked the upper and the lower airways in a similar process.
TREATMENT OF ALLERGIC INFLAMMATION
Traditional allergy therapy includes avoidance techniques, medications, and immunotherapy ("allergy shots").
Over the years, an artificial separation between the treatment of asthma and allergic rhinitis has developed. There are several explanations for this. First, highly effective topical medicines (steroids) for both conditions have been developed. The tendency, then, has been for the physician to treat one condition or the other. Second, CPT codes create an artificial distinction. Finally, practice parameters have been developed for treating rhinitis or asthma, with little mention of treating concomitant disease. However, it has become more evident that effective treatment of asthma must involve treatment of associated nasal disease, and that such treatment of nasal disease can improve asthma symptoms.
EFFECT OF TREATING NASAL ALLERGIES ON THE COURSE OF BRONCHIAL ASTHMA
Ajitihistamine therapy has traditionally been used for treating only upper airway allergies. In fact, physicians have been reluctant to use antihistamines for patients with asthma due to concerns over airway "drying" (mucous inspissation). However, these fears are unfounded. Not only are antihistamines safe in asthma, but studies by Corren et al.4 have shown their modest efficacy in treating asthma. According to Corren et al., 5 mg of loratadine and 120 mg of pseudoephedrine twice daily improved morning wheeze, dyspnea, and tightness in patients with allergic rhinitis and mild seasonal asthma. Morning peak flow measurements were also improved. This is reviewed in more detail in the article by Hurwitz in this issue.
Highly potent topical nasal steroids have emerged as first-line therapy for allergic rhinitis. All symptoms of allergic inflammation are controlled with nasal steroids. Although there has been some question of the safety of nasal steroids in children (see below), their use in the pediatric population has increased.
Initial studies on treating asthma associated with allergic rhinitis with nasal steroids could not rule out intrapulmonary deposition or systemic absorption.5 However, more recent studies suggest that nasal steroids can not only decrease nasal symptoms, but also improve asthma symptoms.4
Watson et al. studied 21 patients with perennial allergic rhinitis and asthma.5 Treatment with nasal aqueous beclomethasone for 4 weeks resulted in significant improvement in global nasal symptoms compared with placebo. Although global asthma symptoms did not change, there was a significant change in bronchial hyperreactivity (as measured by methacholine challenge), and in evening and morning asthma symptom scores in the group treated with nasal beclomethasone.5 Similarly, in a study by Corren et al., nasal beclomethasone was found to prevent the increase in bronchial hyperresponsiveness after exposure to seasonal pollens in patients who had existing asthma and allergic rhinitis.4
The mechanism by which nasal steroids may improve asthma is unknown. Because less than 2% of nasal steroids are delivered to the chest, a direct effect on the lungs is unlikely.5 Furthermore, although older preparations of nasal steroids may have significant bioavailability, it is felt that the amount that would get into the bloodstream after being swallowed would not have a direct effect on the total upper and lower airway inflammatory process.4
SAFETY ISSUES WITH NASAL STEROIDS
Highly potent topical nasal steroids are effective for treating allergic rhinitis. However, recent studies have alerted physicians to possible safety concerns, especially regarding potential growth suppression in children.
A recent study by Skoner et al.6 showed that children treated daily for 1 year with nasal beclomethasone had a suppression of growth of 1 cm, compared with control subjects. This prompted the Food and Drug Administration to add a warning label to all nasal steroids, alerting physicians to this possible effect. However, Schenkel et al.7 showed no growth effect in children as young as 3 years using intranasal mometasone furoate. This product, which has the lowest absolute bioavailability of any nasal steroid, was also recently approved for treatment and prophylaxis of seasonal and perennial allergic rhinitis in children as young as 3 years.
Nasal allergies and allergic asthma should not be viewed as separate diseases. Rather, treatment should be directed toward both conditions. Both antihistamines and nasal steroids, long thought to treat only the upper airway, may have an effect on the lower airway as well. Therefore, the practitioner treating asthma should not neglect the nose. Further studies are needed to delineate underlying mechanisms.
1. Dykewicz M, Fineman S. Executive summary of Joint Task Force practice parameters on diagnosis and management of rhinitis. Ann Allergy Asthma Immunol. 1998;81:463-468.
2. Smith JM. Epidemiology and natural history of asthma, allergic rhinitis, and atopic dermatitis (eczema). In: Middleton E Jr, Reed CE, Ellis EF, Adkinson NF Jr, Yunginger IW, eds. Allergy Principles and Practice, 3rd ed. St. Louis, MO: Mosby; 1988:891-929.
3. Simons FE. Allergic rhinobronchitis: the asthma-allergic rhinitis link. J Allergy Clin Immunol. 1999;104:534-540.
4. Corren J, Adinoff AD, Buchmeier AD, Irvin CG. Nasal beclomethasone prevents the seasonal increase in bronchial responsiveness in patients with allergic rhinitis and asthma. / Allergy Clin Immunol. 1992;90:250256.
5. Watson WT, Becker AB, Simons FE. Treatment of allergic rhinitis with intranasal corticosteroids in patients with mild asthma: effect on lower airway responsiveness. / Allergy Clin Immunol. 1993;91:97-101.
6. Skoner DP, Rachelefsky GS, Meltzer EO, et al. Detection of growth suppression in children during treatment with intranasal beclomethasone dipropionate. Pediatrics. 2000;105:e23. Available at: www.pediatrics.org/cgi/ content/ full/ 00/ 2 /e23.
7. Schenkel EJ, Skoner DP, Bronsky EA, et al. Absence of growth retardation in children with perennial allergic rhinitis after one year of treatment with mometasone furoate aqueous nasal spray. Pediatrics. 2000;105:e22. Available at: www.pediatrics.org / cgi / content/ full / 00 / 2 / e22.