US Pharm. 2023;48(7):15-16.

Complex Respiratory Condition

Asthma is a chronic condition that affects millions worldwide, causing breathing difficulties and negatively impacting quality of life. Asthma’s cause, symptoms, and severity differ from person to person because of the many subtypes of asthma that exist. Approximately 5% to 10% of those with asthma have severe symptoms that are minimally responsive to traditional treatment. In the past 20 years, research has focused on identifying these subtypes to develop more targeted and effective treatments. Among the various subtypes of asthma, high-eosinophilic asthma (eos asthma) stands out as a distinct and challenging form of asthma due to the severity of symptoms and lower treatment effectiveness.

Subtype of Severe Asthma

Eosinophils are a type of white blood cell involved in the immune response. In normal circumstances, they help fight off parasites and regulate inflammation. However, in eos asthma, these cells are present in excessive amounts in the airways, leading to persistent inflammation and asthma symptoms. What distinguishes eos asthma from other asthma types is the elevated level of eosinophils in the blood, sputum, or both. This condition is commonly associated with severe asthma symptoms, frequent exacerbations, and poor response to standard asthma treatments.

The underlying cause of eos asthma is not fully understood. A combination of genetic predisposition and environmental factors contribute to the onset. Some individuals have a genetic susceptibility to develop eosinophilic inflammation. At the same time, exposure to allergens, air pollutants, respiratory infections, and certain medications can trigger or worsen the condition. Many individuals with eos asthma do not have a history of allergic conditions, such as hay fever, food allergy, eczema, or other allergies.

Emerging Treatment Advances

Diagnosing eos asthma requires careful evaluation by a healthcare professional. The diagnosis often involves a thorough medical history, physical examination, lung function tests, and assessment of eosinophil levels in the blood or sputum. Additionally, physicians use imaging studies such as chest x-rays or CT scans to evaluate the severity of airway inflammation. Often, individuals with asthma are not diagnosed with eos asthma until traditional therapies have failed to reduce symptoms.

With a diagnosis of eos asthma, treatment focuses on reducing inflammation and managing symptoms. The primary goal is to achieve and maintain asthma control to prevent exacerbations and improve the patient’s quality of life. Matching individuals to a therapeutic approach that will benefit them the most is an ongoing challenge. Treatment options typically include the following:

Inhaled Corticosteroids: These anti-inflammatory medications are a cornerstone of asthma therapy and can serve as a maintenance treatment for eos asthma.

Long-Acting Beta-Agonists (LABAs): LABAs are bronchodilators that work by relaxing the airway muscles, allowing easier breathing. They are commonly combined with inhaled corticosteroids to relieve symptoms and improve lung function.        

Leukotriene Modifiers: These medications block the action of leukotrienes, which are inflammatory molecules involved in asthma. Leukotriene modifiers are an add-on therapy for individuals with difficulty achieving asthma control with other medications.

Oral Corticosteroids: In severe cases or during exacerbations, short treatment courses with oral corticosteroids may be prescribed to suppress inflammation and improve symptoms quickly. However, long-term use of oral corticosteroids should be avoided due to potential side effects.

Biological Therapies: More recently, biological medications have been developed that specifically target eosinophils and are designed to reduce eosinophilic inflammation. For individuals with severe eos asthma who do not respond well to standard treatments, biological therapy may help. Biological therapies currently approved for eos asthma include bevacizumab, mepolizumab, reslizumab, and dupilumab. Biologics are given via injection or infusion and combined with other medications to control asthma symptoms.

Individuals with eos asthma must work closely with their healthcare team to develop an individualized treatment plan. Regular monitoring of symptoms, lung function, and eosinophil levels is essential for maintaining symptom control and reducing complications.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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