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Increasing incidence of allergic rhinitis and allergic asthma in the Gulf Arabic population
The nose plays a primary role within the airways, working as a filter and air-conditioner.1 Allergen exposure induces nasal symptoms by an immunoglobulin E (IgE)-mediated inflammation, similar to those in allergic asthma. Allergic rhinitis is a prevalent but still underappreciated inflammatory disorder of nasal mucosa. Patients with allergic rhinitis suffer more often from viral and bacterial infections. Worldwide, allergic rhinitis affects around 400 million people, with higher prevalence in industrialized nations.2
Recently an excellent summary on epidemiology, cause, comorbidities, diagnostic algorithm, and treatment was published by Greiner et al.3 The authors provide a comprehensive review of basic science studies as well as clinical trials. Allergic rhinitis has been described as a systemic inflammatory process, which is associated with other inflammatory mucous membrane alterations, such as asthma, rhinosinusitis and conjunctivitis. The majority of the patients with allergic rhinitis develop symptoms before the age of 20. Rhinitis and asthma often coexist. Asthma has been reported by the Global Asthma Report 2011 to be the most common chronic disease among children, and also affects adults.4 Worldwide, 235 million people are reported to suffer from asthma despite the availability of effective treatment. Although allergic inflammation has been held responsible for causing asthma, non-allergic mechanisms might also trigger asthma development.
The prevalence of both asthma and comorbid allergic rhinitis shows an increasing worldwide trend. Allergic rhinitis is a multifactorial disease with genetic as well as environmental risk factors. Indoor and outdoor allergens cause allergic rhinitis, whereas food allergens rarely cause nasal symptoms. Occupational agents, social changes and pollution are regarded as the most important factors responsible for the increasing incidence of allergic rhinitis.
Traditionally, allergic rhinitis has been classified as seasonal or perennial, depending on sensitization to cyclic or year-round allergens. Some patients have both seasonal and perennial allergen sensitization.
Allergic rhinitis is characterized clinically by at least one of the following symptoms: nasal congestion, nasal itching, sneezing, rhinorrhoea and loss of smell (hyposmia). Comorbid allergic conjunctivitis is characterized by eye itching, watering and hyperaemia.
To confirm a diagnosis of allergic rhinitis, specific IgE reactivity to airborne allergens needs to be investigated, mainly by performing skin-prick tests or measuring specific IgE level in serum (RAST). Pharmacotherapy for allergic rhinitis comprises topical nasal treatments as well as oral treatments. As highlighted in reference 3, intranasal corticosteroids are the most effective drugs for allergic rhinitis and are equal or superior to a combination of antihistamine and antileukotriene. Pharmacological treatment with older generations of antihistamines which cause sedation is not recommended because of the negative impact of sedation on academic and work performance and driving.
Subcutaneous and sublingual immunotherapy has been discussed by Marseglia et al.1 and Bousquet et al.2 Immunotherapy should alter the immune system and cure allergic rhinitis in order to prevent chronic rhinosinusitis, polyposis nasi and asthma. Sublingual immunotherapy seems to be safer than subcutaneous immunotherapy as side-effects are restricted to the upper airway tract; sporadic anaphylactic episodes have been reported.
The literature on the prevalence and incidence of allergic rhinitis, indoor and outdoor allergen concentration, and meteorological factors focuses mainly on Europe, the USA and Asia. Only little is known about allergic rhinitis in the United Arab Emirates, the Gulf and the Near East.
At the International Gulf Thoracic 2010 conference it was stated that already one-third of adults in the United Arab Emirates suffer from allergic rhinitis.5 The data presented at the conference have been published previously by Alsowaidi et al.6 The authors carried out an epidemiological survey using a modified questionnaire for allergies in line with the protocols of the International Study of Asthma (ISAAC);4 7550 subjects responded the survey. The results revealed a crude overall prevalence of allergic rhinitis of 36%. In the 13–19 years age group the self-reported prevalence was even higher (41%). The authors blame the increase in allergic rhinitis in the Gulf Arab population on the discovery of oil and the accompanying industrial changes, increased pollution and changes in the environmental landscape, such as building public gardens and plantations in an inland desert. These data confirm the global trend of increasing prevalence of allergic rhinitis and its comorbidities; aetiological mechanisms and therapeutic concepts need to be the focus of further research.
- Marseglia GL, Merli P, Caimmi D, et al. Nasal disease and asthma. Int J Immunopathol Pharmacol 2011; 24(4 Suppl):7–12.
- Bousquet J, Khaltaev N, Cruz AA et al. Allergic Rhinitis and its Impact on Asthma (ARIA) 2008 update (in collaboration with the World Health Organization, GA(2)LEN and AllerGen). Allergy 2008; 63(Suppl 86):8–160.
- Greiner AN, Hellings PW, Rotiroti G, Scadding GK. Allergic rhinitis. Lancet 2011; 378:2112–22 [Epub ahead of print].
- The International Study of Asthma and Allergies in Childhood. http://isaac.auckland.ac.nz/news/newsletters/news201111.pdf
- International Gulf Thoracic 2010 conference. http://www.ameinfo.com/pdfdocs/226995.pdf
- Alsowaidi S, Abdulle A, Shehab A, Zuberbier T, Bernsen R. Allergic rhinitis: prevalence and possible risk factors in a Gulf Arab population. Allergy 2010; 65:208–12.
Professor of ENT
Department of Otorhinolaryngology
Medical University of Vienna
Waehringer Guertel 18–20, A-1090 Vienna, Austria
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