Optimising the management of allergic rhinitis: an Australian perspective

Although often perceived as trivial or “inconvenient”, allergic rhinitis (AR) is a major chronic respiratory disease by virtue of its high prevalence and significant effect on quality of life, work or school performance, and productivity.1

The prevalence of all allergic diseases, including AR, has increased dramatically over the past few decades, particularly in developed countries. One study of self-reported asthma and hayfever in Tasmanian adults revealed the lifetime prevalence of hayfever among adults had doubled from 19.2% in 1968 to 41.3% in 1991–1993.2

Data collected in general practice suggest the national point prevalence of AR is 18.7%, with the highest prevalence among the 25–44-years age group (24.4%).3 Children also feature as sufferers, with the prevalence of current AR at 12% in 6–7-year-olds and 19.6% in 13–14-year-olds.4

For people with AR, quality of life can be considerably reduced, leading to impaired performance of daily activities, cognitive function and classroom productivity, and reduced psychosocial wellbeing.5 AR also creates a significant economic burden: the Australian Institute of Health and Welfare estimated that, in 1994, respiratory disease (including AR) accounted for 8.0% of total healthcare system costs.6

Poorly controlled AR may be associated with various complications and comorbid conditions. AR and asthma frequently co-exist, and AR usually precedes and is a significant risk factor for asthma.1,7-9 Furthermore, evidence shows that treating AR, particularly with intranasal corticosteroids (INCS), can reduce asthma-related emergency department visits and hospitalisations.10 Other conditions that are associated with AR include sinusitis,11 otitis media1,11 and nasal polyposis.1

There have been various international developments in the approach to managing AR. In addition, recent changes to the scheduling of drugs used in treating allergic disease in Australia have important repercussions for the management of this disease and, potentially, for the risk of complications. This article is intended to highlight these changes and address the changing treatment environment for AR in Australia.

AR is a symptomatic disorder of the nose induced by inflammation mediated by immunoglobulin E (IgE) in the membrane lining the nose after allergen exposure.1 Allergic individuals become sensitised to and may develop IgE antibodies against allergens such as pollen, dust mites, animal dander and mould spores. Antigen-specific IgE binds to high-affinity receptors on tissue mast cells.12 On further exposure to the specific allergen, antigen binds to IgE antibodies on the mast cells and mast-cell degranulation occurs, leading to release of chemical mediators (Box 1).12

This immediate allergic response to antigen is termed the early-phase response. The mediators released during this phase include histamine, kinins, neutral proteases, cytokines (such as tumour necrosis factor α) and a variety of interleukins.12 Activation of mast cells also leads to the production of leukotrienes and prostaglandins from arachidonic acid. Together, these mediators result in the characteristic symptoms of AR — watery rhinorrhoea, sneezing and itching — within minutes of allergen exposure.12

This is followed several hours later by the late-phase response, involving the infiltration of inflammatory cells and the release of mediators into the nasal mucosa. The symptoms are essentially the same as in the early-phase response, but congestion predominates.

Diagnosis of AR requires a detailed and accurate history, physical examination, and allergy investigation to assist in characterising the patient and identifying the provoking factors.1 Obtaining a general medical history should be followed by questions on personal and family history of allergic conditions, including eczema, asthma and AR, as well as details of the patient’s environment and occupation. It is important to be mindful that, although the classical symptoms of itching, irritative nose, rhinorrhoea and eye symptoms particularly favour a diagnosis of AR, they are not specific, and may be the result of a viral infection or vasomotor rhinitis. Conversely, their absence does not exclude AR, as blockage may be the predominant symptom in persistent AR. The physical examination should focus on the nose, throat, eyes, ears and, when appropriate, lung function.1

Allergy testing should be undertaken to determine the presence of allergen-specific IgE. This can be done by skin-prick testing or radioallergosorbent test. Allergens are selected according to probability based on clinical history.1 Positive test results should be coupled with clinical features consistent with AR to affirm diagnosis. For more detail on the diagnostic process, readers are referred to a recent article by Puy.13

The original classification of AR was based on the timing of allergen exposure — seasonal or perennial. A newer system, proposed in the Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines in 2001, classifies AR according to the timing of symptom presentation — intermittent or persistent (Box 2).1

The ARIA system is more appropriate for use in Australia for several reasons:

• With the traditional system, “perennial” refers to AR caused by indoor allergens such as dust mites, moulds, insects and animal dander, whereas “seasonal” allergy is related to outdoor allergens such as pollens and moulds. However, in certain regions of Australia, pollens and moulds may be perennial allergens.

• Even patients allergic to “seasonal” allergens may have symptoms for much of the year. For example, in certain regions of Australia, particularly Queensland, it can be very difficult to define the pollen season.

• Most patients are sensitised to multiple allergens — many patients allergic to pollen are also allergic to moulds — meaning that symptoms may be present throughout the year.1

However, there is a continued need for a team approach. When faced with a patient whose condition is unresponsive to OTC treatments, it is important for pharmacists to advise patients to speak to their general practitioner (Box 8). Similarly, GPs can be confident that referral for specialist review of patients with seemingly intractable, chronic or complex disease will provide access to effective alternative treatment options, such as immunotherapy.

The beneficial effects of allergen-specific immunotherapy on symptoms and quality of life in patients with AR are now widely accepted.18 Patients with AR should be considered candidates for immunotherapy based on severity of symptoms, failure of previous treatment strategies, the desire to avoid reliance on pharmacotherapy, and presence of comorbid conditions.18 Box 9 outlines the criteria for selecting candidates for immunotherapy.36 To avoid serious harm, immunotherapy must be prescribed and administered in accordance with the Australian guidelines for asthma.36 That is, it should be prescribed only by practitioners or teams with appropriate expertise, and administered by clinicians with training and experience in this form of treatment, in a setting with adequate resuscitation facilities and equipment.36