Asthma affects millions worldwide, but not all forms are the same. While many experience the common symptoms of wheezing and shortness of breath, one type stands out for its severity: eosinophilic asthma. This challenging variant is driven by an overactive immune response, making it harder to treat with standard asthma medications. 

In this article, we’ll explore what sets eosinophilic asthma apart, how it affects patients, and the latest treatment advances offering better control.

What is eosinophilic asthma?

Eosinophilic asthma is a severe form of asthma that happens when the immune system becomes overly active, leading to increased levels of eosinophils—a type of white blood cell. This chronic inflammation can result in lasting damage to the airways. Here’s what makes it distinct:

• Immune-driven: Unlike asthma triggered by allergens or infections, eosinophilic asthma is driven by an overactive immune response.
• Eosinophil involvement: The body releases excessive eosinophils in response to perceived threats, causing inflammation in the airways.
• Persistent symptoms: This type of asthma leads to chronic, hard-to-control symptoms, such as wheezing, coughing, and shortness of breath.
• Resistance to standard medications: Common asthma treatments like bronchodilators and corticosteroids are often less effective in controlling eosinophilic asthma.

What is the difference between eosinophilic asthma and asthma?

Asthma is typically classified into several different types, including allergic asthma, non-allergic asthma, and exercise-induced asthma, each with its unique characteristics. Eosinophilic asthma stands apart due to its inflammatory nature and resistance to traditional asthma treatments. Here's how it differs from other asthma subtypes:

1. Inflammation type and triggers

Asthma typically involves inflammation in the airways, but the type of inflammation and its triggers can vary significantly between subtypes. Common forms of asthma, like allergic asthma, are primarily triggered by environmental allergens.

• Allergic asthma: In this type, inflammation is caused by exposure to allergens like pet dander, dust mites, mould, or pollen. The immune system reacts by discharging chemicals such as histamine, which leads to airway constriction and typical asthma symptoms.
• Eosinophilic asthma: Unlike allergic asthma, eosinophilic asthma is not primarily driven by allergens. Instead, it results from an overactive immune response where eosinophils, a type of white blood cell, increase and trigger chronic inflammation in the airways. This can occur even in the absence of common allergens, making it harder to identify specific triggers.

2. Severity of symptoms

Eosinophilic asthma is often more severe than other types of asthma, with symptoms that can significantly affect daily life and require more intensive treatment.

• More intense symptoms: Patients with eosinophilic asthma frequently experience severe asthma attacks, even while on standard asthma medications. Persistent symptoms, such as coughing, wheezing, and chest tightness, can severely limit quality of life.
• Airway remodelling: Eosinophilic asthma can cause airway remodelling, where the airway structure is permanently altered, potentially leading to long-term lung damage and impaired lung function.
• Comparison with allergic asthma: While allergic asthma can also cause significant symptoms, it is generally easier to manage through environmental control (e.g., avoiding allergens) and standard medications like inhaled corticosteroids and bronchodilators. The inflammation in allergic asthma tends to be less persistent, making it more responsive to conventional treatments.

3. Treatment response

Eosinophilic asthma often resists traditional asthma treatments, necessitating alternative approaches.

• Resistance to Standard Medications: Eosinophilic asthma does not always respond well to inhaled corticosteroids, which work for allergic asthma. This is due to its immune response, which is less responsive to conventional medications.
• Need for Specialized Treatment: Given the resistance to standard therapies, additional treatments like biologic therapies may be required.
• Biologic Treatments: Biologic treatments target eosinophils, helping to reduce inflammation and manage symptoms more effectively. These treatments provide a breakthrough for severe eosinophilic asthma patients who don’t respond to traditional therapies.

What are the treatment options for severe eosinophilic asthma?

Treating severe eosinophilic asthma requires a more personalised approach, given the nature of the condition. Here’s a look at the typical treatment options for this form of asthma:

1. Inhaled Corticosteroids (ICS)

Inhaled corticosteroids are a cornerstone of asthma management. However, their effectiveness may be limited in eosinophilic asthma. While ICS can reduce general inflammation in the airways, they may not adequately target the eosinophilic inflammation specific to this subtype.

2. Oral Corticosteroids

For patients whose eosinophilic asthma is resistant to inhaled steroids, oral corticosteroids may be prescribed. These medications are typically used for short-term control during an asthma flare-up but are not recommended for chronic use due to the possibility of severe side effects.

3. Biologic Treatments

In more severe cases of eosinophilic asthma, biologic treatments like Fasenra injection containing the active ingredient Benralizumab are becoming more common. 

These treatments work by targeting specific molecules involved in the immune response, thereby reducing eosinophil counts and inflammation. It is a monoclonal antibody that binds to interleukin-5 (IL-5), a protein that helps eosinophils mature and survive. By inhibiting IL-5, This injection effectively lowers eosinophil levels, thus reducing inflammation and asthma symptoms.

These biologic therapies are often given as injections and provide a tailored, long-term treatment option for patients who do not react to standard inhalers or oral steroids.

Wrapping up

Severe eosinophilic asthma is a challenging form of asthma driven by an overactive immune response involving eosinophils, making it less responsive to conventional treatments. Unlike allergic asthma, it requires advanced therapies to manage chronic inflammation effectively. Understanding the differences between asthma subtypes is key to developing personalised treatment plans. With new therapies emerging, individuals with eosinophilic asthma can look forward to improved symptom control and a better quality of life.