Most asthma can be controlled with standard inhalers. A subset of patients continue to have flare-ups, emergency visits, and oral steroid courses despite proper treatment. For these patients, a class of targeted biologic medications may substantially reduce attack frequency and steroid burden in appropriately selected patients.
Severe asthma is defined by international guidelines as asthma requiring high-dose inhaled corticosteroids combined with a long-acting bronchodilator and a second controller — or asthma requiring systemic steroids — to maintain control, or that remains uncontrolled despite this treatment. By that definition, only a small fraction of asthma is severe, but those patients carry a disproportionate burden of symptoms, exacerbations, and steroid-related side effects.
The biology of severe asthma is increasingly well understood. Many patients have a Type 2 (T2-high) inflammatory phenotype driven by eosinophils, IgE, and specific cytokines. Identifying this phenotype is the key to choosing among the modern biologic therapies, which can reduce attacks by 50% or more and often allow patients to come off oral steroids entirely.
Evaluation confirms the asthma diagnosis with spirometry and reviews inhaler technique and adherence — both of which are surprisingly common contributors to apparent treatment failure. A complete asthma evaluation also looks for comorbidities that worsen asthma control: chronic rhinosinusitis with polyps, obstructive sleep apnea, gastroesophageal reflux, and vocal cord dysfunction.
Biomarker phenotyping guides biologic selection. This typically includes blood eosinophil count, total IgE, specific IgE testing to perennial allergens, and FeNO (fractional exhaled nitric oxide) when available.
Optimization of inhaled therapy and trigger management is the foundation. For patients who remain uncontrolled, biologic therapy is added. The available biologics include omalizumab (Xolair) for allergic asthma, mepolizumab (Nucala) and benralizumab (Fasenra) for eosinophilic asthma, dupilumab (Dupixent) for Type 2 inflammatory asthma, tezepelumab (Tezspire) for broad severe asthma indications, and reslizumab (Cinqair) as an additional eosinophilic option.
Selection is individualized to the patient's phenotype, comorbidities, and personal preference. Many patients also benefit because the same biologic addresses coexisting nasal polyps, eczema, or EoE — providing one treatment for multiple conditions.
The first visit reviews your asthma history, prior treatments, and exacerbation pattern. Spirometry and biomarker labs are ordered. At follow-up, results are reviewed and a biologic recommendation is discussed if appropriate. Coordination with your primary care physician and any pulmonologist involved is standard.
Every patient’s situation is different, but the decision logic for severe asthma generally follows these steps. This is not a script — it is a structure that gets adapted to each patient’s history, findings, and goals.
Donald L. McNeil, MD · Board Certified in Allergy & Immunology and Internal Medicine
This page is provided for educational purposes and does not substitute for clinical judgment or direct medical advice. Treatment decisions are individualized based on your full history, examination, and laboratory findings. If you have an emergency, call 911.