Asthma Diagnosis and Management

Definition and Pathophysiology

Asthma is a chronic inflammatory disorder of the airways characterized by three distinct pathophysiologic responses: inflammation, bronchial hyperresponsiveness, and airway remodeling, according to the Journal of Allergy and Clinical Immunology 1
There is a strong genetic component to asthma, with 80% of children with two asthmatic parents developing asthma, as reported by Praxis Medical Insights 2
Gene-environment interactions are critical in the development of asthma, and environmental exposures during immune development are essential, as noted by Praxis Medical Insights 2
In utero exposures, such as maternal smoking, increase the risk of childhood asthma in a dose-dependent pattern, according to Praxis Medical Insights 2

Asthma is a clinical diagnosis requiring episodic symptoms of airflow obstruction plus demonstration of reversible airway obstruction using spirometry, as stated by the American Academy of Family Physicians 3
The American Academy of Family Physicians recommends that diagnosis be based on episodic symptoms of airflow obstruction, including difficulty breathing, chest tightness, cough, wheezing, and symptoms triggered by exercise or allergens 4
Spirometry is mandatory for initial assessment, evaluation of treatment response, and assessment every 1-2 years, as recommended by the American Academy of Family Physicians 4
Bronchoprovocation testing, such as methacholine or histamine challenge, can be useful when asthma is suspected but spirometry is normal, as noted by the Journal of Allergy and Clinical Immunology 1

Disease severity is determined by pulmonary function measurements, asthma symptoms, and need for rescue medication before starting treatment, as stated by the American Academy of Family Physicians 4
The American Academy of Family Physicians notes that classification is based on pre-treatment symptoms, and once treatment begins, classification becomes difficult 4

Managing asthma long-term requires four components: assessment and monitoring, patient education, control of environmental factors and comorbid conditions, and medications using a stepwise approach, as recommended by the Journal of Allergy and Clinical Immunology 1
The American Academy of Family Physicians recommends inhaled corticosteroids as the standard of care for persistent asthma, with combination therapy with long-acting beta-agonists for patients who do not respond to inhaled corticosteroids alone 5
Praxis Medical Insights notes that transitioning from oral corticosteroids to inhaled therapy requires careful monitoring and reduction of prednisone by 2.5 mg weekly during inhaled corticosteroid therapy 4
The American Academy of Family Physicians recommends spirometry for initial assessment, treatment response evaluation, and at least every 1-2 years, as well as written action plans with or without peak flow monitoring 4
Praxis Medical Insights suggests that stress and psychological factors can amplify airway inflammatory responses, and addressing both psychological stressors and physical triggers is important for patients with stress-related exacerbations or depression 6

Allergic asthma is often associated with personal or family history of atopic conditions, including eczema and allergic rhinitis, and symptoms worsen after exposure to pollens, dust, feathered or furry animals, according to the European Respiratory Society 7, 8
Cough variant asthma presents with nonproductive cough as the predominant or sole symptom without wheeze, and responds to standard asthma treatment, as recommended by the American Thoracic Society 7, 8

New-onset asthma caused by workplace exposures is characterized by variable airflow limitation and hyperresponsiveness due to occupational environment factors, as stated by the European Respiratory Society 9, 10
IgE-mediated occupational asthma develops after a latency period with sensitization to high-molecular-weight agents, and is often associated with rhinitis, conjunctivitis, atopy, and early asthmatic reactions, according to the Occupational Safety and Health Administration 9, 10, 11
Irritant-induced occupational asthma may occur with or without latency period, including reactive airways dysfunction syndrome from high-level exposures, as reported by the National Institute for Occupational Safety and Health 9, 10

Removing exposure to the causative agent leads to the best health outcomes in occupational asthma, though complete recovery is not guaranteed even with avoidance, as recommended by the American College of Occupational and Environmental Medicine 9, 10, 11
Relying solely on symptom patterns without objective testing can lead to misdiagnosis, and the inflammatory profile may be similar across different phenotypes, making clinical context essential, according to the National Heart, Lung, and Blood Institute 7, 8