Exhaled nitric oxide is a potential marker of lower airway inflammation. Allergic rhinitis is associated with asthma and bronchial hyperresponsiveness.To determine whether or not nasal and exhaled NO concentrations are increased in allergic rhinitis and to assess the relation between hyperresponsiveness and exhaled NO, 46 rhinitic and 12 control subjects, all nonasthmatic nonsmokers without upper respiratory tract infection, were randomly selected from a large-scale epidemiological survey in Central Norway. All were investigated with flow±volume spirometry, methacholine provocation test, allergy testing and measurement of nasal and exhaled NO concentration in the nonpollen season. Eighteen rhinitic subjects completed an identical follow-up investigation during the following pollen season.Exhaled NO was significantly elevated in allergic rhinitis in the nonpollen season, especially in perennially sensitized subjects, as compared with controls (p=0.01), and increased further in the pollen season (p=0.04), mainly due to a two-fold increase in those with seasonal sensitization. Nasal NO was not significantly different from controls in the nonpollen season and did not increase significantly in the pollen season. Exhaled NO was increased in hyperresponsive subjects, and decreased significantly after methacholine-induced bronchoconstriction, suggesting that NO production occurs in the peripheral airways.In allergic rhinitis, an increase in exhaled nitric oxide on allergen exposure, particularly in hyperresponsive subjects, may be suggestive of airway inflammation and an increased risk for developing asthma. Eur Respir J 1999; 13: 301±306. Previous studies have shown that a significant proportion of those with allergic rhinitis without bronchial symptoms have a bronchial hyperresponsiveness to methacholine [1± 3]. Moreover, this responsiveness seems to increase during the allergen season [3]. Thus, there seems to be a link between the existence and the severity of allergic rhinitis and the degree of responsiveness in the lower airways. The reason for this is not clear. Nasal obstruction resulting in mouth breathing, with impaired filtration and conditioning of the inspired air and increased inhalation of aeroallergens might be a cause. Another hypothesis is that inflammatory mediators may be aspirated from the inflammatory area in the nose into the lower airways, thereby causing a more widespread inflammation. Topical intranasal corticosteroid treatment reduces the release of inflammatory mediators [4], and beclomethasone dipropionate 400 mg daily is more effective in preventing the seasonal increase in bronchial responsiveness when administered topically by intranasal inhalation than by oral inhalation [5]. A third explanation which must be considered is the possible presence of a nasobronchial reflex. Nasal stimulation with methacholine increases airway resistance in the nose, as well as in the lower airways [6]. Other evidence suggestive of this reflex is the increase in bronchial responsiveness to methacho...

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The aim of the present study was to see whether measurements of airway hyperresponsiveness (AHR) and nitric oxide (NO) in exhaled air (ENO) either separately or in combination, could differentiate between asthmatics and healthy control subjects in a population based survey.In central Norway 8,571 adolescents participated in a large-scale epidemiological survey (Young Helseundersùkelsen i Nord-Trùndelag (Health Survey in NorthTrùndelag; HUNT). Asthmatic symptoms when exposed to pollen, pets or house-dust were reported by 7.8% (suspected asthmatics), while 56% reported no asthmatic or allergic symptoms (control subjects). From these respective groups 151 and 213 adolescents were investigated with allergy screening, measurements of exhaled and nasal NO, and methacholine challenge test.AHR (provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second (PD20) <2 mg) was confirmed in 75% of the suspected asthmatics versus 25% of the control subjects, whereas 52% versus 20% had elevated levels of ENO ($8 parts per billion (ppb)). ENO and dose response ratio to methacholine (DRR) were positively correlated (r=0.41, p<0.001). ENO was significantly elevated in atopic versus nonatopic suspected asthmatics (11.7 ppb and 5.6 ppb respectively, p<0.001). Suspected asthmatics with both AHR and atopy had the highest levels of ENO (14.2 ppb).It is concluded that measurements of nitric oxide in exhaled air alone are not a useful tool in diagnosing asthma in population surveys, but that the combination of airway hyperresponsiveness and elevated nitric oxide in exhaled air is a very specific finding for allergic asthma. The use of dose response ratio to methacholine did not provide any additional information to the provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second in this study. Eur Respir J 2000; 15: 849±855.

Background: Subjective health status is the result of an interaction between physiological and psychosocial factors in patients with chronic obstructive pulmonary disease (COPD). However, there is little understanding of multivariate explanations of subjective health status in COPD. The purpose of this study was to explore what determines subjective health status in COPD by evaluating the relationships between background variables such as age and sex, predicted FEV 1 %, oxygen saturation, breathlessness, anxiety and depression, exercise capacity, and physical and mental health.

Atopic dermatitis is often the first and most prevalent manifestation of atopic disease in preschool children. The objectives of the present study were to determine the prevalence and severity of atopic dermatitis in 2-year-old children. Questionnaire data from a total population of 4784 two-year olds and data from a clinical investigation of a sub-sample of 390 children were obtained from a comprehensive prospective study (Prevention of Atopy among Children in Trondheim). The severity of the atopic dermatitis was scored both according to the Nottingham Eczema Severity Score and the Severity Scoring of Atopic Dermatitis. In the total population the prevalence of this disease, defined as any eczema and itchy rash was 16.5% (95% CI: 15.5-17.6). In the subsample, the corresponding prevalence was 20.6% (95% CI: 16.6-24.6) and 15.9% (95% CI: 12.3-19.5) when diagnosed by the UK Working Party's Criteria. More than 70% of the children with UK-diagnosed atopic dermatitis had mild disease according to both the Nottingham Eczema Severity Score and the Severity Scoring of Atopic Dermatitis. The prevalence of atopic dermatitis among 2-year olds was high. However, more than two-thirds of the children had mild disease, which may imply that the impact of atopic dermatitis as a risk factor for future atopic disease is limited.