Am Fam Physician. 2021 Mar 1;103(5):286-290.
Asthma is a common chronic inflammatory disease in the United States. Up to 17% of asthma cases are classified as difficult to treat, and 3.7% of these are considered severe. Uncontrolled asthma is characterized by poor symptom control or frequent exacerbations. In difficult-to-treat asthma, the asthma is uncontrolled despite adherence to inhaled corticosteroid therapy in combination with a second controller, an oral corticosteroid is needed to achieve control, or it is uncontrolled despite oral corticosteroid therapy. Severe asthma is a subset of difficult-to-treat asthma in which the disease is uncontrolled despite adherence to optimal management or it worsens when high-intensity therapy is decreased. The diagnosis of asthma should be confirmed and modifiable factors and comorbidities addressed in patients with difficult-to-treat asthma. An adequate trial of an inhaled corticosteroid and long-acting beta agonist should be implemented with nonbiologic add-on therapies, such as a long-acting muscarinic agent or leukotriene receptor antagonist. Evaluation of severe asthma involves assessment of asthma phenotype. Evidence of type 2 inflammation indicates that the patient may benefit from newer biologic agents. Breathing exercises may improve quality of life, asthma symptoms, lung function, and number of exacerbations. Vitamin D and soy supplementation are ineffective. Bronchial thermoplasty is a procedural option that may be considered if there is inadequate response to other therapies.