A Fresh Look at Allergic Rhinitis
By Neil Gershman, M.D.
Allergic rhinitis (AR) is one of the most common chronic diseases, affecting 20 to 40 million people in the United States. Often referred to by Allergy/Immunology specialists as the "Rodney Dangerfield" of diseases, AR is a significant burden on our society in terms of cost (6 billion dollars in direct US patient care), impaired productivity (3.4 million lost work days), and its co-morbidities (asthma, sinusitis, sleep disturbances, e.g.). Furthermore, sedating antihistamines, which are still widely used for treating AR, have been shown to be hazardous in the workplace and to impair learning in school children. In order to improve the management of AR, the World Health Organization charged a panel of experts to draft a document on AR and its impact on asthma (ARIA).
First, the ARIA guidelines propose a more practical classification scheme for AR. The traditional scheme of "seasonal," "perennial," and "occupational" AR imparts nothing about severity of symptoms and is particularly problematic for populations such as ours in South Florida where seasonal patterns don't exist (see article "Survey of South Florida's Pollen and Spore Counts"). Similar to the familiar scheme for asthma, AR is divided into two subcategories, intermittent and persistent, and graded according to severity of symptoms. "Persistent" symptoms occur more than 4 days per week for more than 4 weeks out of a year, while "moderate to severe" disease effects sleep and significantly impairs work or leisure activities. The guidelines then suggest modes of treatment depending on the classification of a given patient. For moderate-severe, persistent AR, for example, they suggest an intranasal corticosteroid (INCS) with the possible addition of other agents.
In addition to a discussion of traditional agents, the ARIA guidelines present evidence that the leukotriene receptor antagonists or LTRA's (e.g., Singulair® or Accolate®) should be considered as an additional oral agent since leukotrienes are potent mediators of allergic inflammation of the upper airway. A large multi-center trial showed that monotherapy with an LTRA lead to symptomatic improvement of AR similar to that of an antihistamine, and that the combination of the two agents lead to additive benefits. A smaller study showed that a combination of an antihistamine and an LTRA was comparable in efficacy to therapy with an INCS. Two brief points on cost effectiveness:
- The moderate benefit of adding an LTRA may not justify its expense in many patients.
- For persistent AR, monotherapy with an INCS is likely the most cost effective, especially since most patients can be maintained at half the recommended dose.
- In moderate-severe persistent AR, high medication cost may justify specialist referral for allergen vaccine therapy.
The main thrust of the ARIA guidelines, however, is the role of treating AR in the management and possible prevention of asthma. First, the diseases often co-exist, with nearly 90% of asthmatics having some form of rhinitis and approximately 30% of rhinitis patients having asthma. Also, AR is a major risk factor for the development of asthma, with one study showing that 31.8% of AR patients develop asthma within 10 years. Although no direct evidence exists, it is thought that aggressive management of AR, including allergen avoidance measures, can decrease the risk of developing asthma. Furthermore, in a study with AR patients who already had asthma, nasal steroids alone lead to an improvement in asthma symptoms.
These ARIA guidelines provide an organized framework which can be used by physicians in the practical treatment of allergic rhinitis. It also stresses the importance of optimizing the management of this disease, especially in terms of its impact on the treatment and prevention of asthma.
Reference: Bousquet J, Van Cauwenberge P, Khaltaev N. Allergic rhinitis and its impact on asthma. J Allergy Clin Immunol 2001;108(Suppl):S147-S334.