Allergic Rhinitis


Figure 1: Prevalence and Diagnosis of Allergic Rhinitis in a Cross-sectional Study Across Six European Countries


Population 10,000 persons 23 % suffer from allergic rhinitis


70 % patients self aware


30 % patients unaware


45 % not diagnosed


55 % with medical diagnostic


47 % not medicated


53 % medicated Adapted from Durham SR et al., 2000.16


Figure 2: Most Troublesome Symptoms in Adults and Children with Allergic Rhinitis


Nasal congestion


Itchy palate Runny nose Itchy eyes


Sneezing


Watering eyes Itchy ears


Itchy nose 0 % 7 4 7 4‡ 4 3


10 % 20 % 30 % 40 % 50 % 60 % 70 % Adults


Children


*Statistically significant difference Source: Shedden, 2005.111


†Small base (n=69) ‡Small base (n=68)


There are several reports that indicate the incidence of AR in asthmatic adults can be as high as 58 %.44–46


These two diseases are often comorbid:


may also include increases in airborne pollution, increases in dust mite populations in sealed or inadequately ventilated offices and homes with central heating and air conditioning and the current trend towards more sedentary lifestyles.23,24


Another controversial hypothesis proposed to explain the increase in AR prevalence is the ‘hygiene hypothesis’, which suggests that improved sanitation, particularly in developed countries, has prevented the exposure of infants and young children to the range of microbial antigens required to develop normal immune defences.25–29


The critical period for


developing long-lasting immunity is during the first two years of life. A lack of immune challenge during this period can lead to an immature or inappropriate immune system, opening the way to allergen-induced inflammatory airway diseases, such as AR.24,30


The hygiene hypothesis


also links the development of allergic diseases to such factors as immunisation with a variety of vaccines and the use of antibiotics in infants and young children, and has gained extensive support among respiratory specialists and immunologists over the last decade.27,29,31


AR is currently poorly controlled by first-generation H1 antihistamines, which are often less effective and can be associated with undesirable side effects that can include: sedation, headaches, nausea, insomnia


112 The Role of Antihistamines


although this is often a challenge given the ubiquity of aeroallergens. Subsequent pharmacological therapy may include intranasal corticosteroids, oral antihistamines, intranasal antihistamines, decongestants, saline, sodium cromolyn and antileukotrienes.42 Topical corticosteroids have been shown to be effective in attenuating both antigen presentation and late-phase symptoms, and lead to clinically significant reductions in the major symptoms, including nasal blockage. While they are associated with various local and systemic adverse events when used at higher doses or in the very


EUROPEAN RESPIRATORY DISEASE


The first action to take when a person with symptoms suggestive of AR presents is to identify and remove any causal triggers from the environment,56,57


epidemiologically, up to 40 % of patients with AR also have asthma, and up to 80 % of patients with asthma experience nasal symptoms.47–50 Historically, there is clearly a link between the triggers of asthma and AR, with mucosal inflammation a major feature in both diseases. Moreover, the inflammatory mechanisms that occur are similar in both conditions, characterised by an inflammatory infiltrate consisting of eosinophils, T cells and mast cells that release several mediators including chemokines, cytokines and systemic immunoglobulin E (IgE) molecules (see Figure 3).49,51,52 Ultimately, these newly generated inflammatory cells enter the circulatory system, from where they are selectively recruited to the target organs (lungs and nose), exacerbating airway inflammation.49,53,54


Studies


examining the treatment of AR in asthma patients have shown that AR treatment improves asthma symptoms, lowers overall costs and reduces hospitalisations, suggesting that upper-airway disease is a significant risk factor for asthma.55


18 19 18 20 13 9† 12 9 48 58* Unrecognised


Undiagnosed/ underdiagnosed


Not treated, Undertreated, Maltreated


Nasal cavity: allergic rhinitis


and constipation or diarrhoea. Their use can no longer be recommended.32


The inability to control the symptoms contributes to loss of sleep, daytime fatigue, learning impairments and loss of long-term productivity. The most troublesome symptoms in both adults and children include: nasal congestion, itchy eyes, a runny nose and an itchy palate (see Figure 2). Nasal congestion as a result of AR leads to an increased likelihood of developing moderate to severe sleep-disordered breathing.31,33–36


Several older clinical studies


More recent epidemiological studies have also identified a causal relationship between AR and major depression.27 A study by Cohen et al. examined over 700 children; analysis revealed that children with AR at five or six years of age were twice as likely to experience a major depressive episode over the next 17 years.40 A further study examined data from 6,836 adults and found that subjects with AR were again twice as likely to have been diagnosed with major depression in the previous 12 months.41


observed a high occurrence of allergy accompanying patients with depression.37–39


Comorbidities with a Common Basis AR has been associated with a number of other related disorders involving the upper and lower respiratory tract. Short-term complications include acute sinusitis, eustachian tube dysfunction (otitis media with effusion), sleep-disordered breathing, decreased cognitive functioning and aggravation of underlying asthma.42,43 Long-term complications include chronic sinusitis, aggravation of nasal polyps, permanent hearing impairment as a result of chronic otitis, sleep apnoea and sleep-disordered breathing, craniofacial abnormalities, decreased long-term productivity and increased propensity to develop asthma.7,43


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