Guidance for Identifying Severe Asthma

With severe asthma affecting an estimated 10% to 15% of patients with asthma, the condition is causing a significant health burden, affecting activities of daily living, quality of life, morbidity, mortality, and healthcare costs.  The first step in providing treatment for severe asthma is accurately assessing and diagnosing patients, spurring a session at the annual ACAAI meeting offering a thorough review to help clinicians provide accurate and individualized assessment and management.

The Global Initiative for Asthma (GINA) defines severe asthma as ‘‘asthma that requires Step 4 or 5 treatment, e.g., high-dose inhaled corticosteroid (ICS)/long-acting beta agonists (LABAs), to prevent it from becoming ‘uncontrolled,’ or asthma that remains ‘uncontrolled’ despite this treatment.’’ (For detailed information on GINA Steps 1–5, visit https://ginasthma.org/2018-pocket-guide-for-asthma-management-and-prevention/).

The American Thoracic Society and European Respiratory Societies jointly defines severe asthma as one or more of the following:

• Poor symptom control
• Frequent severe exacerbations
• Serious exacerbations
• Airflow limitation
• Controlled asthma that worsens on tapering of high doses of ICS, systemic CS, or additional biologics

For detailed information on those five categories, visit thoracic.org.

Presenter Daniel J. Jackson, MD, of the University of Wisconsin School of Medicine and Public Health in Madison, outlined three specific categories of information required to asses a patient for severe asthma. The medical and treatment history should include current medication use and adherence, steroid burden and recent escalation, history of exacerbations, and any comorbidities. The clinical assessment should review symptoms and questionnaires such as the Asthma Control Test, Asthma Control Questionnaire,  Asthma Impact Survey, and Asthma Quality of Life Questionnaire. Laboratory testing should include spirometry, blood eosinophils, serum IgE, allergy testing of the skin, fractional exhaled nitric oxide, and chest x-ray and/or computed tomography.

Severe asthma and uncontrolled asthma are two distinct conditions, but they share some features, making differential diagnosis challenging. Their shared features include poor adherence, persistent environmental exposures, psychosocial factors, and comorbidities. Other factors also may complicate differential diagnosis, such as rhinitis and rhinosinusitis, obesity, obstructive sleep apnea, gastroesophageal reflux disease, and vocal cord dysfunction.

Jackson told attendees that differential diagnosis may require assessing for and/or ruling out a long list of other conditions: congenital or acquired immunodeficiency, primary ciliary dyskinesia, cystic fibrosis, vocal cord dysfunction, central airway obstruction, recurrent aspiration, bronchiolitis, gastroesophageal reflux disease, psychogenic hyperventilation, chronic obstructive pulmonary disease, heart failure, drug use, and pulmonary embolism.

Just how does a clinician distinguish between severe asthma and uncontrolled asthma or any of the other possible diagnoses? First, Jackson said to confirm the diagnosis of asthma by confirming evidence of airflow obstruction. Second, confirm the patient’s adherence to treatment and make sure they are using inhalers correctly. Watch the patient use it, Jackson said, and demonstrate the correct method (poor adherence may indicate uncontrolled asthma). Lastly, identify any risk factors (e.g., smoking, allergens) and assess for comorbidities, subsequently managing them.

This session was provided by ACAAI and supported by an educational grant from GlaxoSmithKline.