Evaluation and treatment of the patient with allergic rhinitis
Intranasal corticosteroids. Intranasal corticosteroids are the most effective medication in the treatment of allergic rhinitis. Available preparations in the US include beclomethasone diproprionate, budesonide, funisolide, fluticasone propionate, mometa-sone furoate, and triamcinalone acetonide. A meta-analysis identified 16 randomized controlled trials (RCTs) that compared antihistamines with intranasal corticosteroids in a total of 2767 patients. Intranasal corticosteroids provided significantly greater relief from nasal discharge, sneezing, pruritis, and postnasal drip. There was no statistically significant difference between the 2 in reduction of eye symptoms.21
Although this review did not address quality of life, other studies have shown that both triamcinolone acetonide and fluticasone propionate are superior to loratadine in improving quality of life.22,23 Few studies provide any guidance in choosing one intranasal steroid over another. Generally, they are of equal efficacy in patient-oriented outcomes.24,25 Although intranasal corticosteroids are considered daily or “maintenance” medications, a single small RCT of 26 patients showed that fluticasone propionate improved quality of life and reduced symptoms compared with placebo when used on an as-needed basis over a 4-week period.26 More studies are needed to confirm this preliminary finding, though.
Antihistamines. Although not as effective as intranasal steroids, antihistamines do reduce symptoms of rhinorrhea, sneezing, and itching.27 First-gen-eration antihistamines (diphenhydramine, chlorpheniramine, etc.) are lipophilic and cross the blood-brain barrier, resulting in varying degrees of anticholinergic side effects. Placebo-controlled studies have confirmed that these agents cause psychomotor retardation, sleepiness, and decreased work production.5,28 Specifically they seem to affect attention, memory, and vigilance. These symptoms may persist even after an overnight period of sleep.28,29 Second-generation antihistamines (fexofenadine, loratadine, etc.) do not penetrate the brain as well and are less likely to cause central nervous system effects.
However, a recent RCT involving 63 elementary school students challenges findings from previous studies. Children who received diphenhydramine, 25 mg twice daily, performed no differently on computerized reaction-time tests or multiple-choice learning tests than did children who received placebo or loratadine, 10 mg daily.30 Another RCT involving 845 patients from ages 12 to 65 years evaluated quality of life as well as work and school performance of patients who received fexofenadine or placebo. While quality-of-life scores and work performance improved significantly with fexofenadine, there was no significant difference between the groups in school performance.31 Direct comparisons of antihistamines are rare and the results are conflicting. There are no data to show that one of the first-generation antihistamines is superior to the others. Similarly, second-generation drugs are no more effective than the older medications; they only have fewer side effects. Among the second-generation antihistamines, fexofenadine and cetirizine appear to be more effective then loratadine.29
Decongestants. Systemic and topical decongestants relieve the congestion that accompanies the secondary phase of an allergic reaction.4 They have limited effects on other allergic symptoms and, as a result, are often used in combination with antihistamines.32 When used for more than 10 days, topical decongestants (oxymetazoline, xylometazoline) are associated with rebound congestion (rhinitis medicamentosa).33
Leukotriene receptor antagonists. Although not approved by the FDA for treatment of allergic rhinitis, the leukotriene receptor antagonist montelukast was shown in a randomized double-blinded trial to be as effective as loratadine in relieving symptoms. There was minimal additional benefit in using the medications concomitantly.34
Cromolyn sodium. Cromolyn sodium has been shown to prevent the onset of allergic rhinitis symptoms in multiple placebo-controlled trials.35 It is extremely safe but requires regular use and is not as effective as other medications for acute symptoms. Direct comparison studies have shown that cromolyn is not as effective as intranasal corticosteroids.35,36
Immunotherapy. Subcutaneous immunotherapy (SIT) is recommended by all guidelines for patients who fail to respond to pharmacotherapy and allergen avoidance.2,5,10,27 It is recommended in particular for allergic rhinitis secondary to ragweed, grasses, molds, and dust mites. Immunotherapy induces the creation of protective IgG and inhibits the inflammatory response to allergens.27 SIT requires specific allergen confirmation with either a skin test or in vitro assay. Preparation of SIT doses should be done by a practitioner well trained in mixing and diluting extracts.5,37 Forty-three placebo-controlled, double-blind studies have evaluated the efficacy of SIT for 12 different allergens since 1980.10 Thirty-two trials showed clinical efficacy, which can be long lasting. A study of patients treated for 3 to 4 years with immunotherapy for grass pollen allergy showed continued clinical remission for at least 3 years after treatment was stopped.38
Herbal therapies. Alternative approaches to the treatment of allergic rhinitis warrant further investigation. Herbal medications, such as licorice, gingko, and ginseng, are currently used to treat allergic rhinitis, although there are no large studies to confirm their effectiveness.39
