Persistent nocturnal cough in childhood: a population based study

Phenotypic characteristics, healthcare use, and treatment in children with night cough compared with children with wheeze

OBJECTIVES

Population-based studies of children with dry night cough alone compared with those who also wheeze are few and inconclusive. We compared how children with dry night cough differ from those who wheeze.

METHODS

LuftiBus in the school is a population-based study of schoolchildren conducted between 2013 and 2016 in Zurich, Switzerland. We divided children into four mutually exclusive groups based on reported dry night cough (henceforth referred as "cough") and wheeze and compared parent-reported symptoms, comorbidities, exposures, FeNO, spirometry, and healthcare use and treatment.

RESULTS

Among 3457 schoolchildren aged 6-17 years, 294 (9%) reported "cough," 181 (5%) reported "wheeze," 100 (3%) reported "wheeze and cough," and 2882 (83%) were "asymptomatic." Adjusting for confounders in a multinomial regression, children with "cough" reported more frequent colds, rhinitis, and snoring than "asymptomatic" children; children with "wheeze" or "wheeze and cough" more often reported hay fever, eczema, and parental histories of asthma. FeNO and spirometry were similar among "asymptomatic" and children with "cough," while children with "wheeze" or "wheeze and cough" had higher FeNO and evidence of bronchial obstruction. Children with "cough" used healthcare less often than those with "wheeze," and they attended mainly primary care. Twenty-two children (7% of those with "cough") reported a physician diagnosis of asthma and used inhalers. These had similar characteristics as children with wheeze.

CONCLUSION

Our representative population-based study confirms that children with dry night cough without wheeze clearly differed from those with wheeze. This suggests asthma is unlikely, and they should be investigated for alternative aetiologies, particularly upper airway disease.

Cough and cough hypersensitivity as treatable traits of asthma

Cough is a common and troublesome symptom in people with asthma and is often associated with poorer asthma control and exacerbations. Apart from asthma, other causes or comorbidities might underlie cough in asthma, such as rhinosinusitis and bronchiectasis. Eosinophilic inflammation and bronchoconstriction can lead to an acute episode of cough or worsen chronic cough. Cough hypersensitivity with laryngeal paraesthesia, allotussia, and hypertussia might underlie the cough of asthma through augmented sensory nerve excitability of upper-airway vagal sensory nerves. Cough associated with bronchoconstriction and type 2 inflammation should respond to inhaled corticosteroids and long-acting β-adrenoceptor agonist therapy. For cough hypersensitivity in adults, speech and language therapy and neuromodulators (eg, gabapentin) could be considered. In children, there is no consistent association of asthma with cough sensitivity or between cough and asthma severity. Further research is needed to realise the potential of cough as a measure of asthma control, to understand the mechanisms of cough in asthma, and to develop safe, effective treatments and a precision-medicine approach to the management of cough in asthma in children and adults.

Otolaryngologic Management of Chronic Cough in School-aged Children: A Review

Importance

The causes of pediatric chronic cough are numerous and span across several medical subspecialties. In addition to the vast array of underlying causes, there are also several different ways to approach and evaluate chronic cough. Given the frequency with which children present to otolaryngology clinics with this problem, a review of common otolaryngologic causes and an algorithm for evaluation and treatment can be beneficial.

Observations

The primary 3 causes of pediatric chronic cough presenting to an otolaryngologist include infectious causes, reflux, and airway hyperreactivity. In these cases and other instances of specific cough, treatment should be directed at the underlying cause-which may include supportive care, antibiotics, antireflux medication, bronchodilators, inhaled steroids, or other intervention. Patients with nonspecific cough should be treated according to pediatric-specific cough algorithms.

Conclusions and Relevance

Appropriate workup and treatment of chronic cough can lead to higher cure rates, shorter cough duration, and improved quality of life for both patients and caregivers. A systematic approach using cough algorithms can help otolaryngologists effectively manage this common yet complex problem.

Prolonged Cough in Pediatric Population First Line Care, Belgian Guidelines

BACKGROUND

The clinical approach to a prolonged cough, i.e. a cough lasting more than three weeks, is challenging for general practitioners as well for primary care pediatricians. What the recommended clinical approach in primary care is, how cough duration or cough characteristics impact the diagnosis, and what the efficiency and safety of antibiotics or symptomatic treatments are remain in question for primary care physicians.

OBJECTIVE

The last Belgian guidelines were published in 2006 and needed to be reviewed. Those background questions were used to conduct our guideline updating procedure.

METHODS

We systematically performed a pyramidal literature search between the periods 2006-2014 in order to write evidence based guidelines. The data of the literature was summarized, discussed by the authors, experts and the Belgian primary care guidelines committee. Recommendations were formulated and scored following the GRADE classification.

RESULTS

The consultation history as well as the physical examination should be directed towards searching for warning signs (GRADE 1B) and towards the common etiologies depending on cough duration (GRADE 2C). If the cough lasts for more than eight weeks, chest radiography and spirometry should be considered (GRADE 2C). An antibiotic is recommended for a prolonged wet cough (over eight weeks) if prolonged bacterial bronchitis is suspected (GRADE 1B). In the absence of clinical signs of a specific etiology of a cough, no drug can be recommended (GRADE 1B). For all cases, it is initially suggested to avoid irritants (GRADE 1C) as well as to take into account the concerns of parents and inform them about the natural development of a cough.

CONCLUSIONS

More research is needed to provide evidence on the clinical pathway on prolonged cough for primary care. Cough duration of more than eight weeks and prolonged wet cough are the most useful cough characteristics. Regarding a specific cough treatment, no medication has proved any effect greater than placebo. Attention to environmental triggers and patient-centered care remain the keystones of interventions.

Prevalence of cough throughout childhood: A cohort study

Background

Cough in children is a common reason for medical consultations and affects quality of life. There are little population-based data on the epidemiology of recurrent cough in children and how this varies by age and sex, or between children with and without wheeze. We determined the prevalence of cough throughout childhood, comparing several standardised cough questions. We did this for the entire population and separately for girls and boys, and for children with and without wheeze.

Methods

In a population-based prospective cohort from Leicestershire, UK, we assessed prevalence of cough with repeated questionnaires from early childhood to adolescence. We asked whether the child usually coughed more than other children, with or without colds, had night-time cough or cough triggered by various factors (triggers, related to increased breathing effort, allergic or food triggers). We calculated prevalence from age 1 to 18 years using generalised estimating equations for all children, and for children with and without wheeze.

Results

Of 7670 children, 10% (95% CI 10–11%) coughed more than other children, 69% (69–70%) coughed usually with a cold, 34% to 55% age-dependently coughed without colds, and 25% (25–26%) had night-time cough. Prevalence of coughing more than peers, with colds, at night, and triggered by laughter varied little throughout childhood, while cough without colds and cough triggered by exercise, house dust or pollen became more frequent with age. Cough was more common in boys than in girls in the first decade of life, differences got smaller in early teens and reversed after the age of 14 years. All symptoms were more frequent in children with wheeze.

Conclusions

Prevalence of cough in children varies with age, sex and with the questions used to assess it, suggesting that comparisons between studies are only valid for similar questions and age groups.

Validation of a Comprehensive Early Childhood Allergy Questionnaire

BACKGROUND

Parental questionnaires to assess incidence of pediatric allergic disease have been validated for use in school-aged children. Currently, there is no validated questionnaire-based assessment of food allergy, atopic dermatitis (AD), and asthma for infants and young children.

METHODS

The Comprehensive Early Childhood Allergy Questionnaire was designed for detecting AD, asthma, and IgE-mediated food allergies in children aged 1-5 years. A nested case-control design was applied. Parents of 150 children attending pediatric outpatient clinics completed the questionnaire before being clinically assessed by a pediatrician for allergies. Sensitivity, specificity, and reproducibility of the questionnaire were assessed.

RESULTS

Seventy-seven children were diagnosed with one or more current allergic diseases. The questionnaire demonstrated high overall sensitivity of 0.93 (95% CI 0.86-0.98) with a specificity of 0.79 (95% CI 0.68-0.88). Questionnaire reproducibility was good with a kappa agreement rate for symptom-related questions of 0.45-0.90.

CONCLUSIONS

Comprehensive Early Childhood Allergy Questionnaire accurately and reliably reflects the presence of allergies in children aged 1-5 years. Its use is warranted as a tool for determining prevalence of allergies in this pediatric age group.

Nocturnal dry cough in the first 7 years of life is associated with asthma at school age

BACKGROUND

Childhood wheeze is an important, well-known risk factor for asthma, yet little is known about the contribution of nocturnal dry cough. We investigated the association of nocturnal dry cough at ages 1-7 years with doctor-diagnosed asthma at 8 years of age, both in the presence and absence of wheeze.

METHODS

Data of 3,252 children from the PIAMA birth cohort were studied. Parents reported the presence of nocturnal dry cough, wheeze, and doctor-diagnosed asthma in the past 12 months yearly, from birth up to the age of 8 years.

RESULTS

Nocturnal dry cough without wheeze was significantly associated with doctor-diagnosed asthma at age 8, except for age 1 (range of Relative Risks (RR) at ages 2-7: 1.8 (age 5) - 7.1 (age 7), all P-values <0.048). As expected, wheeze without nocturnal dry cough was strongly associated with doctor-diagnosed asthma at age 8 (range of RR: 2.0 (age 1) - 22.2 (age 7), all P-values <0.003). Of interest, nocturnal dry cough with wheeze showed the strongest association with doctor-diagnosed asthma at age 8 (range of RR: 3.7 (age 1) - 26.0 (age 7), all P-values <0.001). The relative excess risk of asthma at age 8 due to interaction of nocturnal dry cough with wheeze at age 1 year was 1.8 (0.1-3.6, P < 0.01).

CONCLUSION

Nocturnal dry cough and wheeze in early childhood are both independently associated with asthma at school age. The presence of both nocturnal dry cough and wheeze at age 1 almost doubles the risk of asthma at age 8 compared to wheeze alone.

Children with chronic nonspecific isolated cough

BACKGROUND

This study observed children with chronic nonspecific isolated cough (NIC) to investigate clinical differences between children whose symptoms resolved spontaneously and those who eventually developed asthma and then explored the differences among the children who eventually developed asthma in terms of their time of response to a trial of inhaled corticosteroid (ICS).

METHODS

Children with chronic NIC were managed either with a wait-and-review approach or with a 2-week trial with 400 μg/d inhaled budesonide according to the preference of their parents. Responses were monitored with a validated cough score. Treatment was prolonged to 8 weeks in the case of partial responders. All children were followed up at 3-month intervals.

RESULTS

A total of 109 children (median [interquartile range] age, 5 [3.5-9] years; cough duration, [8-16] weeks]) were followed for a mean (± SD) time of 21(± 5) months. Cough did not recur in 71% (spontaneous resolution) but relapsed in 28% of the children who later responded to ICS treatment again (asthma). Aeroallergen sensitization (relative risk, 2.86; 95% CI, 1.17-6.99) and previous history of chronic cough (relative risk, 2.68; 95% CI, 1.10-6.49) increased the risk of asthma. Cough duration, the cough score, the family history of asthma, and serum eosinophilia were not found discriminative for the final diagnosis. There were no differences among children who eventually developed asthma and responded to either the 2-week or 8-week trial in terms of the study parameters.

CONCLUSIONS

Chronic NIC does not recur in the majority of children. Initial response to the ICS trial may be misleading but the trial may be preferred for children who have atopic sensitization, a previous history of chronic cough, or both .

Recurrent wheeze and cough in young children: is it asthma?

A clinical diagnosis of asthma is often considered when a child presents with recurrent cough, wheeze and breathlessness. However, there are many other causes of wheeze in a young child. These range from recurrent viral infections to chronic suppurative lung disease, gastro-oesophageal reflux disease and rare structural abnormalities. Arriving at a diagnosis includes taking into consideration the symptomatology, triggers, atopic features, family history, absence of red flags and therapeutic trial, where indicated.

Chronic cough in children

The management of chronic cough, a common complaint in children, is challenging for most health care professionals. Millions of dollars are spent every year on unnecessary testing and treatment. A rational approach based on a detailed interview and a thorough physical examination guides further intervention and management. Inexpensive and simple homemade syrups based on dark honey have proved to be an effective measure when dealing with cough in children.

Feasibility study: honey for treatment of cough in children

Respiratory tract infections are an important health problem because of high incidence and economic costs. The World Health Organization identifies honey as a potential demulcent treatment for cough. The aim of this study is to determine: i) patient public perceptions towards a proposed randomized controlled trial (RCT) comparing the effects of honey to placebo for treatment of cough in children; ii) potential participation rates for proposed trial; iii) whether age and gender of parent or child impacts on proposed cough assessment tools. Forty adult participants with children age 1-6 years presenting with an upper respiratory tract infection were enrolled. They underwent a structured interview regarding the proposed trial and assessed their child's cough using two validated questionnaires. Eighty-eight percent of those recruited were willing to participate in the proposed trial. The two independently validated cough scores correlated well. A relationship between age and gender of child or parent with cough assessment score was not found. We conclude that a RCT to determine the effects of honey versus placebo is feasible. The public find the outcome measures and trial design acceptable.

An observational study on cough in children: epidemiology, impact on quality of sleep and treatment outcome

Background

Cough is one of the most frequent symptoms in children and is the most common symptom for which children visit a health care provider.

Methods

This is an observational study on acute cough associated with upper respiratory tract infection (URTI) in children. The study evaluates the epidemiology and impact of cough on quality of sleep and children's activities, and the outcome of cough with antitussive treatments in pediatric routine clinical practice. Study assessments were performed through a pediatric cough questionnaire (PCQ), developed by the Italian Society of Cough Study. A total of 433 children visited by family care pediatricians for acute cough due to a URTI were enrolled in this study, with mean age of 6.1 years (SD 3.6). Cough type, duration, severity and frequency, cough impact on sleep disturbances of children and parents and on school and sport activities were assessed at baseline. In a subset of 241 children who were either treated with antitussive drugs (levodropropizine n = 101, central antitussives n = 60) or received no treatment (n = 80), the outcome of cough after 6 days was analyzed in terms of resolution, improvement, no change, or worsening. Descriptive analysis, χ² test, and multivariate analysis with stepwise logistic regression were performed.

Results

Cough disturbed sleep in 88% of children and 72% of parents. In children treated with cough suppressants, the duration, type, intensity, and frequency cough were similar at baseline in the two groups respectively treated with levodropropizine and central antitussives (cloperastine and codeine). Both levodropropizine and central drugs reduced cough intensity and frequency. However, percentage of cough resolution was higher with levodropropizine than with central antitussives (47% vs. 28% respectively, p = 0.0012).

Conclusions

Acute cough disturbs sleep in most children and their parents. Both levodropropizine and central antitussives reduced cough intensity, with levodropropizine producing a higher cough resolution rate.

Increased interleukin-4 and decreased interferon-γ levels in serum of children with asthma

BACKGROUND AND PURPOSE

Immune and inflammatory responses, mediated by cytokines, play important roles in the pathophysiology of asthma. These responses are associated with over expression of T helper (Th)-2 cytokine, particularly interleukin (IL)-4 and IL-5, and decreased expression of Th-1 cytokine, IL-2 and IFN-γ. We hypothesized that there would be an imbalance in the levels of circulating IL-4 and IFN-γ in the asthmatic subjects.

METHOD

We investigated serum levels of IL-4 and IFN-γ among eighty children (18 steroid-naïve, 30 steroid-treated children with asthma and 32 healthy controls) using commercially available ELISA kits.

RESULTS

Serum level of IL-4 was significantly higher in steroid-naïve group of asthmatic children compared to the healthy control subjects and was lower in steroid-treated group though the level was statistically not significant. In contrast, serum levels of IFN-γ were significantly lower in both steroid-naïve and steroid-treated groups of asthmatic children compared to healthy control subjects.

CONCLUSION

The results of our study suggest that serum level of IL-4 may be elevated in concert with decreased level of IFN-γ in asthma. Determination of serum levels of IL-4 and IFN-γ may be a useful tool for understanding the disease processes in asthma.

Predictive factors for airway hyperresponsiveness in children with respiratory symptoms

BACKGROUND

Asthma diagnosis is a challenging condition, particularly in patients without obstructive pattern and reversibility on spirometry. Determination of airway hyperresponsiveness (AHR) may be helpful, but the procedure is time-consuming and not always practical.

OBJECTIVE

To determine the potential factors that may predict the presence of AHR in children with asthmalike symptoms but without obstructive pattern and reversibility on spirometry.

METHODS

All patients with asthmalike symptoms but without obstructive pattern and reversibility on spirometry were analyzed retrospectively between January 9, 2007, and December 30, 2009. The features of clinical history and laboratory results were analyzed with univariate and multivariate regression analysis.

RESULTS

A total of 111 children between 6 and 18 years of age, with a median age of 10.2 years, were analyzed, and AHR was detected in 67 patients (60.3%). Multivariate logistic regression analysis revealed coexistence of nocturnal cough and exercise-induced cough (odds ratio [OR], 22.1; 95% confidence interval [CI], 3.1-159.2; P = .004), eosinophilia (OR, 18.7; 95% CI, 1.9-178.7; P = .01), and borderline bronchodilator response in forced expiratory volume in 1 second (between 7% and 11%) (OR, 10.1; 95% CI, 2.1-49.1; P = .004) as significant risk factors for the presence of AHR, whereas exercise-induced dyspnea was found to be related to the absence of AHR (OR, 0.2; 95% CI, 0.1-0.8; P = .02).

CONCLUSION

In children with asthmalike symptoms but with normal spirometry, certain features of clinical history and laboratory results can strongly predict the presence of AHR and may help less frequent use of challenge tests.

Mono and multifaceted inhalant and/or food allergen reduction interventions for preventing asthma in children at high risk of developing asthma

BACKGROUND

Allergen exposure is one of the environmental factors seemingly associated with the development of asthma. If asthma is a multi-factorial disease, it is hypothesised that prevention might only prove effective if most or all relevant environmental factors are simultaneously avoided.

OBJECTIVES

To assess effect(s) of monofaceted and multifaceted interventions compared with control interventions in preventing asthma and asthma symptoms in high risk children.

SEARCH STRATEGY

We searched the Cochrane Airways Trials Register (December 2008).

SELECTION CRITERIA

Randomised controlled trials of allergen exposure reduction for the primary prevention of asthma in children. Interventions were multifaceted (reducing exposure to both inhalant and food allergens) or monofaceted (reducing exposure to either inhalant or food allergens) Follow up had to be from birth (or during pregnancy) up to a minimum of two years of age.

DATA COLLECTION AND ANALYSIS

We included in the analysis studies assessing the primary outcome (current diagnosis: asthma) and/or one of the secondary outcomes (current respiratory symptoms: wheezing, nocturnal coughing and dyspnoea). We pooled multifaceted and monofaceted intervention trials separately. We made an indirect comparison of their effects using tests for interaction to calculate relative odds ratios.

MAIN RESULTS

We included three multifaceted and six monofaceted intervention studies (3271 children). Physician diagnosed asthma in children less than five years, and asthma as defined by respiratory symptoms and lung function criteria in children aged five years and older, both favoured treatment with a multifaceted intervention compared to usual care (< 5 years: odds ratio (OR) 0.72, 95% confidence interval (CI) 0.54 to 0.96, and > 5 years: OR 0.52, 95% CI 0.32 to 0.85). However, there was no significant difference in outcome between monofaceted intervention and control interventions (< 5 years: OR 1.12, 95% CI 0.76 to 1.64, and > 5 years: OR 0.83, 95% CI 0.59 to 1.16). Indirect comparison between these treatments did not demonstrate a significant difference between multiple interventions and mono-interventions in reducing the frequency of asthma diagnosis in children under five years (relative OR 0.64 (95% CI 0.40 to 1.04, P = 0.07) or five years and older (relative OR 0.63, 95% CI 0.35 to 1.13, P = 0.12). There was also no significant difference between either mono- and multifaceted intervention and control in reducing the likelihood of symptoms of nocturnal coughing at follow up. Wheezing, however, showed a significant difference between multifaceted and mono-interventions (relative OR 0.59, 95% CI 0.35 to 0.99, P = 0.04), but the significance was lost when data on treatment only was analysed.

AUTHORS' CONCLUSIONS

The available evidence suggests that the reduction of exposure to multiple allergens compared to usual care reduces the likelihood of a current diagnosis of asthma in children (at ages < 5 years and 5 years and older). Mono-intervention studies have not produced effects which are statistically significant compared with control. In children who are at risk of developing childhood asthma, multifaceted interventions, characterised by dietary allergen reduction and environmental remediation, reduce the odds of a physician diagnosis of asthma later in childhood by half. This translates to a number needed to treat (NNT) of 17. The effect of multi-faceted interventions on parent reported wheeze was inconsistent and had no significant impact on nocturnal coughing or dyspnoea. Data from monofaceted intervention exposed children studies were not significantly different from those of control groups for all outcomes. There remains uncertainty as to whether multiple interventions are more effective than mono-component interventions. The comparisons made were indirect, making the conclusions drawn uncertain. To our knowledge there are no ongoing studies in which both intervention strategies are randomly compared. The findings, however, warrant further direct comparison between multiple- and monofaceted interventions aimed at reducing the prevalence of asthma in children.

Cough and asthma

The relationship between cough and asthma is complex. Epidemiological studies now suggest that most children with recurrent cough who do not wheeze do not have asthma. These children are commonly described as having non-specific cough that appears to be due to increased cough receptor sensitivity during the coughing episode. Children with asthma who cough have also been shown to have increased cough receptor sensitivity during an acute exacerbation. Cough severity does not generally correlate with asthma severity. Apart from wheeze and dyspnoea, there are no clear distinguishing features to separate asthma from non-specific cough. To date, no specific treatment has clearly been shown to benefit children with non-specific cough. Although a trial of asthma treatment may be justified in these children, it is preferable to cease rather than escalate treatment if there is no response. In children with asthma who cough, cough should not be used as the predominant symptom to direct asthma therapy.

Guidelines for evaluating chronic cough in pediatrics: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To review relevant literature and present evidence-based guidelines to assist general and specialist medical practitioners in the evaluation and management of children who present with chronic cough.

METHODOLOGY

The Cochrane, MEDLINE, and EMBASE databases, review articles, and reference lists of relevant articles were searched and reviewed by a single author. The date of the last comprehensive search was December 5, 2003, and that of the Cochrane database was November 7, 2004. The authors' own databases and expertise identified additional articles.

RESULTS/CONCLUSIONS

Pediatric chronic cough (ie, cough in children aged <15 years) is defined as a daily cough lasting for >4 weeks. This time frame was chosen based on the natural history of URTIs in children and differs from the definition of chronic cough in adults. In this guideline, only chronic cough will be discussed. Chronic cough is subdivided into specific cough (ie, cough associated with other symptoms and signs suggestive of an associated or underlying problem) and nonspecific cough (ie, dry cough in the absence of an identifiable respiratory disease of known etiology). The majority of this section focuses on nonspecific cough, as specific cough encompasses the entire spectrum of pediatric pulmonology. A review of the literature revealed few randomized controlled trials for treatment of nonspecific cough. Management guidelines are summarized in two pathways. Recommendations are derived from a systematic review of the literature and were integrated with expert opinion. They are a general guideline only, do not substitute for sound clinical judgment, and are not intended to be used as a protocol for the management of all children with a coughing illness. Children (aged <15 years) with cough should be managed according to child-specific guidelines, which differ from those for adults as the etiologic factors and treatments for children are sometimes different from those for adults. Cough in children should be treated based on etiology, and there is no evidence for using medications for the symptomatic relief of cough. If medications are used, it is imperative that the children are followed up and therapy with the medications stopped if there is no effect on the cough within an expected time frame. An evaluation of the time to response is important. Irrespective of diagnosis, environmental influences and parental expectations should be discussed and managed accordingly. Cough often impacts the quality of life of both children and parents, and the exploration of parental expectations and fears is often valuable in the management of cough in children.

Bronchial sensitivity and bronchial reactivity in children with cough variant asthma

BACKGROUND

Cough variant asthma (CVA) is diagnosed in some children with chronic cough who do not have wheezing. However, the precise mechanism of CVA in children is unclear.

OBJECTIVE

To evaluate the physiologic differences in the airways of children with classic asthma and CVA, the methacholine dose-response curves of respiratory resistance (Rrs) were studied.

PATIENTS AND METHODS

CVA was diagnosed in 31 children with chronic cough (age range, 5 to 14 years; 19 boys and 12 girls; mean age, 8.5 years) on the basis of methacholine inhalation challenge using an oscillation method. For comparison, the study included 86 age-matched children with classic asthma (age range, 5 to 15 years; 42 boys and 44 girls; mean age, 9.5 years), 25 age-matched children with cough (age range, 5 to 15 years; 17 boys and 8 girls; mean age, 8.8 years), and 23 age-matched control subjects (8 boys and 15 girls; mean age, 9.2 years). Consecutive doses of methacholine were doubled until a 200% increase in Rrs from baseline was reached. The cumulative dose of methacholine at the inflection point of Rrs was considered to represent the bronchial sensitivity to inhaled methacholine (minimum dose of methacholine [Dmin]). The slope of the methacholine dose-response curve (SRrs), which was considered to represent bronchial reactivity, was measured from the increasing Rrs curve.

RESULTS

The values of Dmin in classic asthma patients and in CVA patients were significantly lower than those for cough patients and control subjects. There was no significant difference in the values of Dmin between the classic asthma and CVA patients. The value of SRrs in CVA patients was significantly lower than that in classic asthma patients, cough patients, and control subjects (p < 0.05, p < 0.01, and p < 0.01, respectively). There was no significant difference in the value of SRrs between classic asthma patients, cough patients, and control subjects.

CONCLUSIONS

These data show that bronchial reactivity in the children with CVA was significantly lower than that in the children with classic asthma, and this specificity has an effect on prolonged cough without wheezing in children with CVA.

Inhaled corticosteroids for non-specific chronic cough in children

BACKGROUND

Cough in isolation of other clinical features is known as non-specific cough, which has been defined as non-productive cough in the absence of identifiable respiratory disease or any known aetiology. In children with non-specific cough the possibility of asthma being the underlying disorder is often raised (so called cough variant asthma). The proponents of cough variant asthma suggest a therapeutic trial of medications usually used to treat asthma.

OBJECTIVES

To determine the efficacy of inhaled corticosteroids in non-specific cough in children over the age of two years.

SEARCH STRATEGY

Searches were conducted on Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Searches were current as of March 2004.

SELECTION CRITERIA

All randomised (randomised and quasi-randomised) controlled clinical trials in which an inhaled corticosteroid (beclomethasone (BDP), fluticasone (FP), triamcinalone (TAA) or any other corticosteroid) were given for cough in children over two years of age were included. Two review authors independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

Data from trials was extracted by both review authors and entered into the Cochrane Collaboration software program RevMan Analyses 1.0.2.

MAIN RESULTS

Two trials met the inclusion criteria (123 participants). One compared inhaled beclomethasone dipropionate (400 micrograms per day) with placebo and the other compared fluticasone propionate (2 mg per day for 3 days followed by 1 mg per day for 11 days) with placebo. Both studies used metered dose inhalers via a spacer. With the lower dose of inhaled corticosteroid there was no significant difference between the beclomethasone and placebo groups. With the higher dose there was a significant improvement in nocturnal cough frequency after two weeks in children presenting with persistent nocturnal cough. However, a significant but smaller improvement was also seen with placebo.

AUTHORS' CONCLUSIONS

In one study beclomethasone dipropionate (400 micrograms per day) was no different from placebo in reducing the frequency of cough measured objectively or scored subjectively. There might be a small improvement with very high-dose inhaled corticosteroid but the clinical impact of this is unlikely to beneficial.

Cough: are children really different to adults?

Worldwide paediatricians advocate that children should be managed differently from adults. In this article, similarities and differences between children and adults related to cough are presented. Physiologically, the cough pathway is closely linked to the control of breathing (the central respiratory pattern generator). As respiratory control and associated reflexes undergo a maturation process, it is expected that the cough would likewise undergo developmental stages as well. Clinically, the 'big three' causes of chronic cough in adults (asthma, post-nasal drip and gastroesophageal reflux) are far less common causes of chronic cough in children. This has been repeatedly shown by different groups in both clinical and epidemiological studies. Therapeutically, some medications used empirically for cough in adults have little role in paediatrics. For example, anti-histamines (in particular H1 antagonists) recommended as a front-line empirical treatment of chronic cough in adults have no effect in paediatric cough. Instead it is associated with adverse reactions and toxicity. Similarly, codeine and its derivatives used widely for cough in adults are not efficacious in children and are contraindicated in young children. Corticosteroids, the other front-line empirical therapy recommended for adults, are also minimally (if at all) efficacious for treating non-specific cough in children. In summary, current data support that management guidelines for paediatric cough should be different to those in adults as the aetiological factors and treatment in children significantly differ to those in adults.

A comparison of risk factors for wheeze and recurrent cough in preschool children

In a study of 2,978 Danish children aged 5 years from two suburban counties of Copenhagen, carried out in 1998, the authors compared risk factor profiles for wheeze and recurrent cough without wheeze by using polytomous logistic regression to clarify whether the two conditions are likely to have the same etiology. Data were obtained 1) by a mailed parental questionnaire (International Study of Asthma and Allergies in Childhood questions and supplementary questions on cough, sociodemography, perinatal factors, and environmental exposure); 2) through general practitioners (familial allergic disease); and 3) from the National Medical Birth Register (birth weight). Wheeze (WH) was defined as more than one episode of wheeze within the last 12 months (irrespective of cough status) and recurrent cough without WH (RC) as cough occurring outside colds and usually lasting for periods of more than 1 week in children with no more than one attack of wheeze within the last 12 months. Risk factors for comparison were selected as those that, after repeated stepwise logistic regression, remained significant for children with WH or RC. Significant differences were found for gender (p = 0.003), gestational age (p = 0.0002), maternal history of asthma (p = 0.0008), and standard of housing condition (p = 0.04)-all risk factors for WH but not RC. Results may suggest that the two conditions have different etiologies.

Inhaled beta2-agonists for treating non-specific chronic cough in children

BACKGROUND

The pathophysiology of so called 'cough variant asthma' has not received a great deal of research interest and opinion lies divided as to whether it is really asthma or not. The proponents of cough variant asthma suggest a therapeutic trial of medications usually used to treat asthma

OBJECTIVES

To determine the effectiveness of inhaled ss2 agonists in non-specific chronic cough in children over the age of 2 years.

SEARCH STRATEGY

The Cochrane Airways Group database (including MEDLINE, EMBASE and CINAHL) and the Cochrane Controlled Trials Register (CCRT) were searched. Additional searching included hand searching of medical journals through the Cochrane Collaboration, references, references of references listed in primary sources and personal communication with authors. In addition "Grey literature" including theses, internal reports, non-peer reviewed journals were sought.

SELECTION CRITERIA

All randomised (randomised and quasi-randomised) controlled clinical trials in which inhaled ss2 agonists were given for chronic cough in children over 2 years of age were included. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

Data for trials of salbutamol versus placebo were extracted by both reviewers and entered into the Cochrane Collaboration software program Review Manager, version 4.2

MAIN RESULTS

In children presenting with isolated chronic cough there was no significant difference between salbutamol treated group and placebo group.

AUTHORS' CONCLUSIONS

Salbutamol was no different from placebo in reducing the frequency of cough measured objectively or scored subjectively.

Cough, wheezing and asthma in children: lesson from the past

Recurrent cough is an important medical and sometimes frustrating problem encountered by pediatricians, especially if it is not associated with wheeze or other evidence of systemic disease. In the past, many children with chronic cough have been diagnosed as asthmatic. However, epidemiological, clinical and laboratory studies conducted over the last ten years elucidated many aspects of the relationship between cough and bronchoconstriction. It is difficult to make a diagnosis of asthma on cough alone, but the setting in which the patient is seen (i.e., in a primary care setting or ain a specialistic clinic) may address doctors to the right diagnosis. A prudent ''wait and see'' approach may be useful in many occasions.

[Chronic cough in childhood]

INTRODUCTION

Although less frequent than viral induced recurrent cough; chronic cough remains a sometimes difficult to resolve diagnostic tool.

STATE OF THE ART

Most authors estimate that a cough can by considered as chronic after three weeks of duration. Few papers have been published concerning etiologic diagnosis of chronic cough in childhood but these indicate the same main causes as in adults: cough variant asthma, postnasal drip syndrome, gastro-esophageal reflux. Nevertheless, each age bracket presents specific diagnosis: malformations between zero and one year, psychogenic cough in adolescents.

PERSPECTIVES

New techniques as induced sputum studies helps to refine chronic cough diagnosis in childhood (after 7 years). Eosinophilic bronchitis, associated or not to bronchial hyperresponsiveness has important therapeutic consequences because associated with a favourable response to corticosteroids. Other techniques will be developed in the future (exhaled NO for example).

CONCLUSIONS

Chronic cough in childhood must be investigated from an anatomic point of view and on frequency arguments. Control and removal of the cough will only be obtained if a precise diagnosis and a suitable treatment are reached.

[Association between atopic dermatitis, allergic rhinitis and asthma in schoolchildren aged 13-14 years old]

BACKGROUND

Atopic dermatitis is closely related to other atopic diseases, especially asthma and allergic rhinitis. Although there is a certain agreement that suffering from atopic eczema predisposes to asthma and allergic rhinitis, the risk of developing these diseases should be quantified in populations following a standardized method, which is the objective of this study.

METHOD

Using the questionnaire from the International Study of Asthma and Allergy in Childhood (ISAAC), we performed a cross-sectional study of all schoolchildren aged 13 and 14 years old in the city of Cartagena (Murcia, Spain). The relationship between atopic dermatitis and its severity with asthma, allergic asthma, and allergic rhinitis was analyzed.

RESULTS

Quantification of risk showed that schoolchildren with atopic eczema had a 3-fold risk of allergic rhinitis (OR: 3.33; 95 % CI: 2.45-4.54), a 4-fold risk of asthma (OR: 3.85; 95 % CI: 2.74-5.42) and a 5-fold risk of allergic asthma (OR: 4.91; 95 % CI: 3.17-7.59) compared with schoolchildren without atopic eczema. The severity of eczema was also directly related to that of asthma and rhinitis.

Childhood cough variant asthma and its relationship to classic asthma

BACKGROUND

In pediatrics, some patients with chronic cough who have no evidence of a causative disease are diagnosed as having cough variant asthma (CVA). The precise prognosis of infants and children with CVA, however, is still unclear.

OBJECTIVE

To evaluate the relationship between CVA and classic asthma in childhood.

METHODS

To diagnose CVA, we performed a methacholine inhalation challenge with use of a transcutaneous oxygen pressure (tcPO2) monitoring system in 100 children with chronic cough, and 75 children (45 boys and 30 girls; mean age, 5.7 years) were diagnosed as having CVA. These patients underwent follow-up monitoring for more than 3 years to ascertain whether classic asthma developed. For comparison, 53 age-matched children with classic asthma (30 boys and 23 girls; mean age, 5.6 years) and 30 age-matched control subjects (12 boys and 18 girls; mean age, 5.5 years) also participated in this study. Consecutive doses of methacholine were doubled until a 10% decrease in tcPO2 from the baseline was reached. The cumulative dose of methacholine at the inflection point of tcPO2 (Dmin-PO2) was considered to represent the sensitivity of tcPO2 to inhaled methacholine.

RESULTS

After 3 years or more of follow-up assessments, 52 of the 75 patients answered our questionnaire. Of the responding patients, 28 had been diagnosed as having classic asthma. A significant difference was noted in the age at onset of CVA between the children in whom classic asthma developed (the asthma-developed group) and those in whom classic asthma did not develop (the asthma-free group). No statistically significant differences in Dmin-PO2 between the asthma-developed group and the asthma-free group or between the girls and the boys, however, were foun

CONCLUSIONS

This study showed that 75% of children with chronic cough had CVA, that classic asthma developed in 54% of the children with CVA, and that it is not the severity of bronchial hyperresponsiveness in CVA but the age at onset of CVA that is a risk factor for the development of classic asthma in childhood CVA.

Extrathoracic airway responsiveness in children with asthma-like symptoms, including chronic persistent cough

Asthma-like symptoms, including chronic persistent cough, are not always specific for classical asthma. In order to investigate whether assessment of extrathoracic airway hyperresponsiveness (EAHR) during methacholine bronchial challenge helped in the evaluation of pediatric patients with asthma-like symptoms such as chronic cough, we examined 133 consecutive, unselected patients (mean age, 10.06 +/- 2.16 years) who had neither established asthma nor bronchial obstruction previously. We recorded the forced mid-inspiratory flow (FIF(50)) as an index of extrathoracic airway narrowing. In addition, a 25% decrease in FIF(50) (PD(25)FIF(50)) below the cutoff concentration of < or = 8 mg/mL methacholine was assumed to indicate EAHR. According to the methacholine response, 81 patients had EAHR, and 41 of them had combined EAHR and bronchial hyperresponsiveness (BHR); 39 patients had only BHR. Airway hyperresponsiveness was not demonstrated in 13 patients and not in any of the control children. When patients with cough as the sole presenting symptom (60.9%) were compared with those with cough and wheeze (20.3%), those with cough alone had a significantly greater probability of having EAHR (OR, 4.16; 95% CI, 1.32-13.13) and a lower probability of having BHR (OR, 0.70; CI, 0.25-1.95) than those with cough and wheeze. Patients with cough, wheeze, and dyspnea (18.8%) had a significantly greater chance of having BHR than those with cough alone (OR, 5.08; CI, 1.55-16.64). Patients with cough and wheeze as compared with those with cough, wheeze, and dyspnea had significantly greater probability of having both EAHR and BHR (OR, 4.71; CI, 1.94-11.47). In order to ascertain the clinical relevance of EAHR, we assessed in the second part of the study whether the effects of treatment of the underlying disease would result in relief of airway hyperresponsiveness. Rhinosinusitis and perennial allergic rhinitis accounted for EAHR in 71 patients, and 34 of them also demonstrated BHR. They received specific therapy for their upper airway diseases for 4 weeks. Compared with values before treatment, FIF(50) and forced expiratory volume in 1 sec (FEV(1)) did not change significantly. The dose of methacholine causing a 20% fall in FEV(1) (PD(20)FEV(1)) and PD(25)FIF(50) values were significantly increased from 2.40 +/- 1.39 to 4.22 +/- 1.13 mg /mL (P < 0.001) and from 1.03 +/- 1.75 to 8.71 +/- 1.21 mg /mL (P < 0.0001), respectively. We conclude that measurements of EAHR and BHR are the most important ways to evaluate children with asthma-like symptoms, including chronic persistent cough when chest X-rays and pulmonary function tests remain within normal limits. Therefore, empirical treatment is not necessary when these investigations are available. Our results suggest that specific treatment of inflammation in the upper airways reversed persistant cough, and may play an important role in modulating lower airways responsiveness in patients with concomitant BHR.

Acute upper airway infections

Upper respiratory tract infections are common and important. Although rarely fatal, they are a source of significant morbidity and carry a considerable economic burden. Numerous therapies for the common cold have no effect on symptoms or outcome. Complications such as cough are not improved by over-the-counter preparations, while labelling cough alone as a symptom of asthma may result in unnecessary use of inhaled steroid treatment. Clinical presentation of sore throat does not accurately predict whether the infection is viral or bacterial, while throat culture and rapid antigen tests do not significantly change prescribing practice. Antibiotics have only a limited place in the management of recurrent sore throat due to group A beta-haemolytic streptococcal infection. Routine use of antibiotics in upper respiratory infection enhances parent belief in their effectiveness and increases the likelihood of future consultation in primary care for minor self-limiting illness. Respiratory viruses play a major role in the aetiology of acute otitis media (AOM); prevention includes the use of influenza or RSV vaccination, in addition to reducing other risk factors such as early exposure to respiratory viruses in day-care settings and to environmental tobacco smoke. The use of ventilation tubes (grommets) in secretory otitis media (SOM) remains controversial with conflicting data on developmental outcome and quality of life in young children. New conjugate pneumococcal vaccines appear safe in young children and prevent 6-7% of clinically diagnosed AOM.

Airway eosinophilia is associated with wheeze but is uncommon in children with persistent cough and frequent chest colds

The role of eosinophilic airway inflammation in the variant asthma syndromes of cough and chest colds is not well defined. We tested the hypothesis that children with persistent cough and chest colds have increased sputum eosinophils, similar to those with wheeze. The parents of 390 primary school children completed a symptoms questionnaire. Children with wheeze (n = 28), cough (n = 12), recurrent chest colds (n = 17), and no symptoms (control subjects, n = 26), underwent allergy skin prick tests, spirometry, hypertonic saline inhalation challenge, and sputum induction, and then completed a peak expiratory flow (PEF) and symptoms diary over a 2-mo period. Children with wheeze had significantly reduced PEF (p = 0.001) and higher sputum eosinophils when compared with the cough, chest cold, and control groups (3.1% versus 0.5%, 0%, 0%; p = 0.03). The prevalence of eosinophilic bronchitis (sputum eosinophils > 2.5%) was 45% in the wheeze group, which was significantly higher than the control group (9.35%, p = 0.04). Eosinophilic bronchitis was present in two children with cough (20%) and two with chest colds (15%, p > 0.05 versus control). In these groups, eosinophilic bronchitis was not associated with airway hyperresponsiveness (AHR) to hypertonic saline (p > 0.05). Children with cough and chest colds reported greater exposure to environmental tobacco smoke. In conclusion, this community-based survey of children with chronic respiratory symptoms has shown that wheeze is a good discriminator for the presence of eosinophilic bronchitis, and that persistent cough and recurrent chest colds without wheeze should not be considered a variant of asthma. Eosinophilic bronchitis did occur in a significant minority of these "variant asthma" syndromes.

[Chronic cough, asthma and allergy]

The medical approach of chronic cough suffers from the lack of a standardised definition. The most frequently encountered criterion is a recurrent cough observed during several consecutive months, each episode lasting at least 1 week. The link between recurrent cough and asthma is still discussed. Cough-related asthma diagnosis is facilitated when wheezing is clearly confirmed, or may be reminded by a nonproductive middle night cough, or an exercise-triggered cough, or the presence of personal or familial atopy. Conversely, an early morning and productive cough associated with tobacco exposure do not suggest asthma.

[Chronic cough in children: etiology and decision trees]

Recurrent or chronic cough can be the symptom of a worrying condition which must be diagnosed without delay (cystic fibrosis, asthma, bronchial foreign body, bronchiectasis). Investigation of recurrent or chronic cough is based on simple principles: careful history-taking concerning the characteristics of the cough, full clinical examination to look for any associated symptoms, and auxological assessment to detect any interruption in weight increase. Only when this initial evaluation has been carried out can complementary investigations be sought. Ordinary respiratory infections that are part of the building up of immunity are predominant in coughs of children aged under 6 years and are aggravated by deleterious factors such as passive exposure to tobacco, early introduction to communal life, and urban pollution. We describe the most frequent causes of cough and their frequency according to the age of the child.

A review of cough in children

Cough is a very common symptom of respiratory disease and reason for parents to seek medical attention. The article presents broad clinical guidelines on the approach to childhood cough and discusses current controversies of the management of cough in children.

Cough in children

Cough is a common presenting problem in children. A persistent moist or productive cough is always abnormal. The history, examination, chest x-ray and spirometry usually provide clues to specific causes of cough. Non-specific cough, defined as a non-productive or dry cough in the absence of identifiable respiratory disease, is poorly understood. We briefly discuss major controversies in non-specific cough and its management in children.

Persistent nocturnal cough: randomised controlled trial of high dose inhaled corticosteroid

OBJECTIVE

To investigate the effect of a short course of inhaled corticosteroid in the treatment of isolated and persistent nocturnal cough in children.

DESIGN

Randomised double blind placebo controlled study.

SETTING

Subjects' homes in east London, England.

SUBJECTS

Consecutively referred children, 1-10 years old, with persistent nocturnal cough.

INTERVENTIONS

Placebo or fluticasone propionate 1 mg twice daily for three nights and 500 microg twice daily for 11 nights. Videotaping of children at night: two nights' baseline, nights 3 and 4 after three days of inhaled corticosteroid, and nights 15 and 16.

MAIN OUTCOME MEASURE

A fall in 75% of coughs from baseline.

RESULTS

50 subjects were recruited. The median number of coughs in the baseline period for the inhaled corticosteroid group and placebo group were 92 and 71, respectively (p = 0.43) and, on nights 15 and 16, 8 and 36, respectively (p < 0. 01). Compared to baseline, both groups of subjects improved significantly by nights 15 and 16 (p < 0.01; p < 0.01). Comparing the inhaled corticosteroid and placebo groups, coughs fell to a median of 22% and 57% of baseline totals on nights 3 and 4, respectively (p = 0.38), and 8% and 35% on nights 15 and 16, respectively (p = 0.02). 17 of 24 subjects on inhaled corticosteroid who completed the study and 8 of 23 on placebo improved by 75% after two weeks (p = 0.03).

CONCLUSIONS

Children with persistent nocturnal cough improve in two weeks after referral on placebo. There is a modest benefit from a two week course of high dose inhaled corticosteroid.

Cough, cough receptors, and asthma in children

This review discusses current general concepts on cough and the relationship between cough, cough receptor sensitivity, and asthma in children. It presents models of the relationship between cough and bronchoconstriction, and proposes a new model outlining the relationship between cough receptor sensitivity, airway hyperresponsiveness, and the clinical issues of cough, wheeze, and dyspnea in children with and without asthma. Cough is very common in children, with a prevalence of 15-20%. Those with non-specific cough (dry cough in the absence of identifiable respiratory illness) are often treated with a variety of drugs, in particular, medications for asthma and gastroesophageal reflux. However, there is little evidence to use these medications for the sole symptom of cough in children. Clinical studies on cough need to be interpreted in light of inherent methodological problems in studying cough. These methodological problems include the nonrepeatable nature of questions on cough, the unreliability of subjective measurements of cough, the lack of objective measurements to quantify cough severity, and the period effect (spontaneous resolution of cough). Although cough can be troublesome, cough serves as an important function for maintaining normal health of the respiratory system. The importance of cough in maintaining respiratory health is reflected in the development of lung atelactasis/collapse from retained secretions and recurrent pneumonia in clinical situations where the cough reflex is ineffective. The cough reflex is complex and still poorly understood. In this article the simplified cough pathway is presented and involves cough receptors, mediators of sensory nerves and the afferent pathway, the vagus nerve, the cough centre, efferent pathway, and cough effectors.

Persistent cough: is it asthma?

The aim of this study was to determine if children in the community with persistent cough can be considered to have asthma. A validated questionnaire was given to the parents of 1245 randomly selected children aged 6-12 years. Atopy was measured with skin prick tests. Children with persistent cough had less morbidity and less atopy compared with children with wheeze. Although the syndrome commonly referred to as "cough variant asthma" could not be shown in this study, a significant number of children with persistent cough had been diagnosed as having asthma and were treated with asthma medications including inhaled corticosteroids. Studies are urgently needed to determine the appropriate treatment for children with persistent cough.

A randomised, placebo controlled trial of inhaled salbutamol and beclomethasone for recurrent cough

AIMS

To test the hypothesis that inhaled salbutamol or beclomethasone will reduce the frequency of cough in children with recurrent cough. A secondary aim was to determine if the presence of airway hyperresponsiveness (AHR) can predict the response.

DESIGN

Randomised, double blind, placebo controlled trial.

METHODS

During a coughing phase, 43 children (age 6-17 years) with recurrent cough were randomised to receive inhaled salbutamol or placebo (phase I) for 5-7 days and then beclomethasone or placebo (phase II) for 4-5 weeks, and in a subgroup of children for 8-9 weeks. The children used an ambulatory cough meter, kept cough diaries, and performed the capsaicin cough sensitivity, hypertonic saline bronchoprovocation, and skin prick tests.

RESULTS

Salbutamol or beclomethasone had no effect on cough frequency or score, irrespective of the presence of AHR.

CONCLUSIONS

Most children with recurrent cough without other evidence of airway obstruction, do not have asthma and neither inhaled salbutamol nor beclomethasone is beneficial.

Prescribing for persistent cough in children

To identify the medications general practitioners consider for the treatment of persistent isolated cough, we undertook a postal questionnaire survey of a sample of general practitioners in east London. Fewer than 10% indicated that they never prescribed for such cough. About 70% sometimes considered antibiotics and/or bronchodilators in all age groups. Inhaled steroids and cromoglycate were considered by about 30% of prescribers for infants compared with over 60% for older age groups. As yet there is no evidence that medication is beneficial for persistent isolated cough. The role of asthma drugs for children with this symptom needs to be evaluated so that we can better identify those who are likely to benefit.

Treatment of childhood asthma. Options and rationale for inhaled therapy

Epidemiological studies suggest the prevalence of asthma is increasing, though some remain sceptical as to the magnitude or indeed the presence of an increase. However, despite improved diagnosis and the availability of the potent drugs now available there remains considerable respiratory morbidity associated with asthma. It is clear from a number of studies that failure to deliver drugs to the lungs when using inhaler devices is a factor contributing to this high level of morbidity. Failure of drug delivery may result from the prescribing of inappropriate devices, failure to use devices appropriately or failure to comply with a treatment regimen. For most of the currently available forms of asthma therapy there are significant advantages to be gained from administering them in aerosol form. The benefits to be derived from administering these drugs as an aerosol include a rapid onset of action for drugs such as beta-agonists and a low incidence of systemic effects from drugs such as beta-agonists and corticosteroids. Over the past 25 years our understanding of the nature of asthma has changed. Though this has been reflected in the emphasis on inhaled corticosteroid therapy in recent guidelines, it has not been reflected in the range of inhaler devices available. Manufacturers continue to place drugs such as corticosteroids in the same devices as short acting beta-agonists even though the requirements for these different drug classes are very different. It is likely that this contributes to suboptimal therapeutic responses with inhaled corticosteroids. However, the variability associated with current delivery systems is relatively small compared with the variability introduced by poor compliance. There is no work currently available to indicate how the use of cheap disposable devises which do not incorporate any form of positive feedback influence compliance with inhaled steroids. Optimising aerosolised drug delivery in childhood involves consideration of the class of drugs, the particular drug within a class but more importantly, the age and abilities of the child. Devices must be selected to suit a particular child's needs and abilities. Devices utilising tidal breathing are generally used such as spacing chambers or, less commonly these days, nebulisers. A screaming or struggling child, or failure to use a closely fitting mask, reduces drug delivery to the lungs enormously. Failure to respond to inhaled therapy in early childhood may be attributable to failure of drug delivery. Drug delivery in early childhood using current devices remains more an art than a science.

Health effects of passive smoking. 3. Parental smoking and prevalence of respiratory symptoms and asthma in school age children

BACKGROUND

A systematic quantitative review of the evidence relating parental smoking to the prevalence of asthma and respiratory symptoms was conducted amongst school age children.

METHODS

Sixty relevant studies were identified after consideration of 1593 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified 25 studies of asthma, 41 of wheeze, 34 of chronic cough, seven of chronic phlegm and six of breathlessness which were included in a quantitative overview.

RESULTS

The pooled odds ratios for either parent smoking were 1.21 (95% CI 1.10 to 1.34) for asthma, 1.24 (95% CI 1.17 to 1.31) for wheeze, 1.40 (95% CI 1.27 to 1.53) for cough, 1.35 (95% CI 1.13 to 1.62) for phlegm, and 1.31 (95% CI 1.08 to 1.59) for breathlessness. Adjustment for confounding had little effect. Evidence of heterogeneity between studies appeared largely explicable by publication bias with a superfluity of small studies with large odds ratios. However, excluding these had little effect on the pooled odds ratios. The prevalence of all symptoms increased with the number of parents who smoked. While maternal smoking had a greater effect than paternal smoking, the effect of father only was clearly significant.

CONCLUSIONS

The relationship between parental smoking and respiratory symptoms seems very likely to be causal given statistical significance, robustness to adjustment for confounding factors, consistency of the findings in different countries, and evidence of dose response. The raised risk in households where the father, but not the mother, smoked argues for a postnatal effect.

Cough sensitivity in children with asthma, recurrent cough, and cystic fibrosis

In adults, cough sensitivity is influenced by gender and is heightened in those with non-productive cough. This study examined if cough sensitivity is (i) altered in children with asthma, recurrent cough, and cystic fibrosis and (ii) influenced by age, gender, or forced expiratory volume in one second (FEV1). Cough sensitivity to capsaicin and spirometry were performed on 209 children grouped by the diagnosis of asthma, recurrent dry cough, cystic fibrosis, and controls. Cough sensitivity was increased in children with recurrent cough, and lower in children with cystic fibrosis when compared with children with asthma and controls. Age influenced cough sensitivity in the controls. In the asthmatics, FEV1 (% predicted) correlated to cough sensitivity measures. There was no gender difference in cough sensitivity. It is concluded that cough sensitivity is different among children with recurrent dry cough, asthma, and cystic fibrosis. In children, age, but not gender, influences cough sensitivity measures and when cough sensitivity is used in comparative studies, children should be matched for age and FEV1.

Effect of capsaicin on airway responsiveness to hypertonic saline challenge in asthmatic and non-asthmatic children

Recurrent cough and asthma are common problems in children. In the evaluation of children with recurrent cough, the sequential measurements of airway responsiveness (AR) and capsaicin cough receptor sensitivity may be useful. However, the effect of capsaicin on AR induced by an indirect stimulus such as hypertonic saline (HS) is not known. Current evidence suggests that a common pathway is involved in both capsaicin and HS challenges. This study was designed to determine whether inhalation of capsaicin for the cough receptor sensitivity test before HS challenge will alter AR of asthmatic and non-asthmatic children to that challenge. Twenty-one children (12 asthmatics, 9 non-asthmatics; mean age, 11.3 years) performed the HS challenge alone or 2 min after capsaicin inhalation on 2 different days in random order. The end point of the capsaicin inhalation was when > or = 5 coughs were stimulated from a single inhalation. The power of the study was > 90% at a significance level of 0.05. Capsaicin inhalation prior to HS challenge did not alter the AR of normal children. In the asthmatic group, the PD15 (provocation dose causing a fall in forced expiratory volume in 1 s of > or = 15% from the baseline) without prior inhalation of capsaicin (mean, 2.44 +/- SEM 1.21 ml) was not significantly different from that when HS challenge was performed after capsaicin inhalation (mean, 2.19 +/- SEM 0.83 ml). The mean of the difference in log PD15 of the HS challenge with and without capsaicin was -0.02 (95% CI, -0.16, 0.12), i.e. within the equivalence range of the HS challenge in children with asthma. We conclude that in normal and asthmatic children, capsaicin inhalation does not alter AR to HS; consequently the capsaicin cough sensitivity test can be performed validly before an HS challenge.

Wheeze, cough, atopy, and indoor environment in the Scottish Highlands

A questionnaire which included items on wheeze, cough, eczema, hay fever, and indoor environment, including parental smoking habits, pet ownership, heating and cooking methods, home insulation, damp, mould, and years lived in their houses, was given to 1801 children, aged 12 and 14 from the Highland Region in Scotland. Of the 1537 (85%) who replied, 267 (17%) reported current wheeze, 135 (9%) cough for three months in the year, 272 (18%) eczema, and 317 (21%) hay fever. There was no consistent relationship between respiratory symptoms and indoor environment although cough was associated with damp, double glazing, and maternal smoking. The prevalence of wheeze, cough, and atopy was higher in children who had lived in more than one house during their lifetime. These results suggest that increasing mobility of families in recent years may be more important in the aetiology of asthma than exposure to any one individual allergen or pollutant.