We searched for English language articles and reviews in PubMed and Cochrane published between inception and Oct 1, 2017. The search combined the terms “Asthma” and the subheadings “epidemiology”, “aetiology”, “exacerbations”, “pathophysiology”, “innate AND adaptive immunity”, “diagnosis”, “therapeutics”, and “prevention”. We prioritised papers published from 2013 onwards. We also searched the reference lists of articles identified by this search and selected those we deemed most relevant.
SeminarAsthma
Section snippets
Epidemiology
Asthma is one of the most common chronic, non-communicable diseases, and affects around 334 million people worldwide.1 The global prevalence of self-reported, doctor-diagnosed asthma in adults is 4·3% (95% CI 4·2–4·4), with wide variation between countries. Prevalence is highest in developed countries—eg, Australia (21·0%)2—and lowest in developing countries—eg, China (0·2%).2 Greater variation is seen for asthma symptoms in children, ranging from 2·8% (Indonesia) to 37·6% (Costa Rica) in
Pathogenesis of asthma
Asthma is a heterogeneous condition in both children and adults. Dissecting this heterogeneity is contributing to our understanding of disease pathogenesis and development of new therapeutic strategies, especially in severe disease. The observable characteristics (phenotype) of asthma—including clinical features of the disease and their underlying mechanisms (endotype)—are complex and represent a multitude of host–environment interactions that occur over different spatial scales (ie, genes to
Definition and clinical presentation
Asthma is a heterogeneous condition characterised by variable respiratory symptoms and variable airflow limitation. These features can be generated by a range of underlying mechanisms that are typically, but not always, associated with airway inflammation and airway remodelling.
Diagnosis of asthma
No gold standard exists for diagnosis of asthma. Diagnosis is probability-based, and considers symptoms and variable expiratory airflow limitation. Asthma is heterogeneous, and for some patients, one or both of these features might not be found.
Many features can increase or decrease the probability that symptoms are due to asthma (appendix). In children, accurate assessment of symptoms and rescue β2 agonist use can be difficult, because most information is given by the parents, who are not
Long-term management
Asthma treatment goals in children and adults are to minimise both the symptom burden (day-to-day symptoms, disturbed sleep, and activity limitation) and the risk of adverse asthma outcomes (exacerbations, persistent airflow limitation, and medication side-effects). Together, these two domains constitute asthma control. For many patients, these goals can be achieved with current treatment approaches. Patients' personal goals might differ from these medical goals, so the clinician should ask
Severe asthma
Severe asthma is defined in the European Respiratory Society and American Thoracic Society guidelines for adults and children aged at least 6 years as asthma that requires treatment with guidelines-suggested medication for GINA steps 4–544 for the past year, or systemic corticosteroids for at least 50% of the past year, to prevent it from becoming uncontrolled, or which remains uncontrolled despite therapy.50 Uncontrolled asthma refers to poor symptom control, frequent severe exacerbations,
Asthma exacerbations
Acute or subacute episodes of increased symptoms—known as exacerbations, asthma attacks, or flare-ups—punctuate the natural course of asthma and require a change in treatment. Exacerbations are characterised by progressively increasing shortness of breath, cough, wheezing or chest tightness, and decreasing lung function. Onset is usually rapid in children, but can develop over a week or more in adults. Exacerbations account for a substantial portion of asthma-related expenditure; they affect
Search strategy and selection criteria
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Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010
Lancet
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Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC phases one and three repeat multicountry cross-sectional surveys
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Medications as asthma triggers
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Allergic rhinitis and sinusitis in asthma: differential effects on symptoms and pulmonary function
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The asthma-COPD overlap syndrome: towards a revised taxonomy of chronic airways diseases?
Lancet Respir Med
(2015)
Fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease: 5-year follow-up
J Allergy Clin Immunol
Similar psychological characteristics in mild and severe asthma
J Psychosom Res
The poorly explored impact of uncontrolled asthma
Chest
Development and cross-sectional validation of the Childhood Asthma Control Test
J Allergy Clin Immunol
Asthma Control Test: reliability, validity, and responsiveness in patients not previously followed by asthma specialists
J Allergy Clin Immunol
Inhaler mishandling remains common in real life and is associated with reduced disease control
Respir Med
Evaluation of a novel educational strategy, including inhaler-based reminder labels, to improve asthma inhaler technique
Patient Educ Couns
Should recommendations about starting inhaled corticosteroid treatment for mild asthma be based on symptom frequency: a post-hoc efficacy analysis of the START study
Lancet
Adherence: the goal to control asthma
Clin Chest Med
Use of beclomethasone dipropionate as rescue treatment for children with mild persistent asthma (TREXA): a randomised, double-blind, placebo-controlled trial
Lancet
Beclometasone–formoterol as maintenance and reliever treatment in patients with asthma: a double-blind, randomised controlled trial
Lancet Respir Med
Budesonide/formoterol maintenance plus reliever therapy: a new strategy in pediatric asthma
Chest
Efficacy and safety of maintenance and reliever combination budesonide-formoterol inhaler in patients with asthma at risk of severe exacerbations: a randomised controlled trial
Lancet Respir Med
Dedicated severe asthma services improve health-care use and quality of life
Chest
Phenotypes determined by cluster analysis in severe or difficult-to-treat asthma
J Allergy Clin Immunol
Acute and chronic systemic corticosteroid-related complications in patients with severe asthma
J Allergy Clin Immunol
Asthma exacerbations and sputum eosinophil counts: a randomised controlled trial
Lancet
Global asthma prevalence in adults: findings from the cross-sectional world health survey
BMC Public Health
A systematic review on the development of asthma and allergic diseases in relation to international immigration: the leading role of the environment confirmed
PLoS One
Gender differences in prevalence, diagnosis and incidence of allergic and non-allergic asthma: a population-based cohort
Thorax
Remission and persistence of asthma followed from 7 to 19 years of age
Pediatrics
Increasing awareness of sex differences in airway diseases
Respirology
A large-scale, consortium-based genomewide association study of asthma
N Engl J Med
Genetic variants regulating ORMDL3 expression contribute to the risk of childhood asthma
Nature
Genetic risk factors for the development of allergic disease identified by genome-wide association
Clin Exp Allergy
Pathogenesis of asthma: implications for precision medicine
Clin Sci (Lond)
Inflammatory subtypes in asthma: assessment and identification using induced sputum
Respirology
T-helper type 2-driven inflammation defines major subphenotypes of asthma
Am J Respir Crit Care Med
A transcriptome-driven analysis of epithelial brushings and bronchial biopsies to define asthma phenotypes in U-BIOPRED
Am J Respir Crit Care Med
Moving towards precision care for childhood asthma
Curr Opin Pediatr
Eosinophil protein in airway macrophages: a novel biomarker of eosinophilic inflammation in patients with asthma
J Allergy Clin Immunol
How much asthma is really attributable to atopy?
Thorax
Allergy in severe asthma
Allergy
Analysis of induced sputum in adults with asthma: identification of subgroup with isolated sputum neutrophilia and poor response to inhaled corticosteroids
Thorax
The immunology of asthma
Nat Immunol
TH2 and TH17 inflammatory pathways are reciprocally regulated in asthma
Sci Transl Med
Interleukin-4 and -13 expression is co-localized to mast cells within the airway smooth muscle in asthma
Clin Exp Allergy
Increased airway smooth muscle in preschool wheezers who have asthma at school age
J Allergy Clin Immunol
Mast-cell infiltration of airway smooth muscle in asthma
N Eng J Med
Lung damage and airway remodelling in severe asthma
Clin Exp Allergy
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