The Evolving Understanding of Eosinophilic-Associated Type 2 Inflammatory Diseases

The understanding of Eosinophilic-Associated Diseases (EADs) has evolved significantly over time.

Initially, attention was focused on Eosinophilic Gastrointestinal Diseases (EGID), with the most focus on Eosinophilic Oesophagitis (EoE). It was undetermined whether these diseases were eosinophil-driven or if eosinophils were merely accompanying a broader pathological process. Over time, it became evident that multiple inflammatory type 2 (T2) pathways contribute to disease development.

As research advanced, it became clear that EADs extend beyond the GI system and involve a broader spectrum of inflammatory T2 conditions. This led to a broader classification of EADs, encompassing upper and lower gut EGID as well as EAD T2 conditions beyond the gut, such as severe asthma - eosinophilic asthma (EA), eosinophilic granulomatosis with polyangiitis (EGPA), Hyper Eosinophilic Disease (HES), chronic Rhinitis - nasal polyps, atopic dermatitis (AD) etc.

Patients with EADs often have a family history of immune-mediated diseases. For example, among the EOS Network community, 80% also have coexisting atopic conditions such as asthma or eczema, highlighting the shared immune mechanisms across these disorders, whether they be associated through co-morbidity (associated) or coexistence.

Professor Stephen Attwood, Independent Consultant in Clinical Trials - Gastroenterology and Surgery:

"About a third of allergy patients seem to have EoE symptoms. Allergy and immunology specialists should routinely ask if patients have difficulty swallowing solid food or how they manage it.

If they have symptoms, they should get an endoscopy immediately.

We need to improve the diagnosis of people with allergies and those with food bolus obstruction (FBO). Right now, we are missing too many cases."

With this growing understanding, EADs are beginning to no longer be seen as isolated organ-specific conditions but as a multi-system immune disorder with common pathological pathways which ultimately require holistic care and treatments.

A breakthrough in treatment came with the approval of biologic therapy, such as Dupilumab, an IL-4/IL-13 inhibitor, which significantly improved outcomes in several EADs: EoE, severe asthma, atopic dermatitis (eczema), and chronic allergic rhinitis with nasal polyps.

This marked a shift from simply managing EAD symptoms to targeted immune therapy for these conditions that share a T2 inflammatory pathway. This means having a single biologic treatment rather than treating the symptoms of each condition separately with multiple treatments for the same patient, described as polypharmacy. 

Also of essential scientific importance was the research data from the failed EoE Benralizumab trial, which targeted IL-5  to deplete eosinophils and showed limited efficacy in reducing EoE symptoms despite successfully reducing eosinophil histology levels. This provided evidence of the complexity of these diseases and that eosinophils play a role but are not necessarily the primary or only driver of inflammation. 

More treatments and research are being studied across various EADs, and the insights of these trials will continue to evolve the understanding and management of these diseases.

Unfortunately, even the approved biological treatments are currently not available everywhere. In many countries, patients urgently need holistic care rather than fragmented treatment for individual conditions that share an underlying immune mechanism.

There are early signs of progress in healthcare specialists diagnosing and managing EADs as a group, rather than as separate diseases. Future research will focus on identifying immune drivers beyond eosinophils and developing next-generation biologic targeted therapies for precision medicine.

Amanda Cordell, CEO&Founder EOS Network

"EOS Network understands the challenge of navigating evolving terminology in Eosinophilic Diseases. Patients and healthcare professionals may encounter different terms for the same conditions as research advances. 

However, what once seemed like separate pieces is now forming a clearer, unified picture. EOS Network remains committed to raising awareness of this broader perspective, advocating for better access to effective treatments, and promoting multi-specialist, holistic patient care."

Eosinophilic Diseases Research: Past, Present and Future

Eosinophilic Oesophagitis in the Atopic March: A Multidisciplinary Strategy for Atopic Diseases

New Screening Tool to Enhance Diagnosis and Management of T2 Inflammation Disorders

Could It Be EoE? Signs & Symptoms Guide