FormalPara Key Summary Points

Eosinophil-associated diseases (EADs) represent a range of heterogeneous conditions in which eosinophils are believed to play a critical pathological role

Patients with EADs face substantial disease burdens, including debilitating symptoms and associated disease flares, and an arduous path to diagnosis and treatment, often involving repeated visits to multiple clinical subspecialties

This charter outlines key rights that patients should expect from the management of their condition(s) and describes an ambitious action plan to improve health outcomes for patients with EADs

Patients and their caretakers, multiple healthcare professionals, and the broader public need greater awareness and education about EADs

All patients with EADs deserve a timely and accurate diagnosis, access to an appropriate multidisciplinary team, and access to appropriate treatments

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The eosinophil is one of a number of white blood cells that make up the immune system [1]. In recent years, a range of inflammatory diseases have been identified across several organ systems and tissues that appear to be driven primarily by abnormal regulation of the number and/or activation state of eosinophils [2,3,4,5,6]. The term eosinophilic immune dysfunction (EID) has recently been used to describe the underlying roles of eosinophils in these respiratory, dermatological, gastrointestinal, and systemic conditions (Table 1) [6, 7]. The range of heterogeneous diseases in which eosinophils are believed to play a critical pathological role can be collectively referred to as eosinophil-associated diseases (EADs) [6, 7].

Table 1 Information about various EADs (presented alphabetically)a

Many people are living with EADs worldwide; this collection of diseases includes common illnesses such as eosinophilic asthma [8, 9], less common eosinophilic gastrointestinal diseases (EGIDs), and rare conditions, such as eosinophilic granulomatosis with polyangiitis (EGPA) [10, 11] and hypereosinophilic syndromes (HES) [2]. People with EADs often face a substantial disease burden, poor health outcomes, and a poor health-related quality of life (HRQoL), which affects both the patient and their support network (e.g. family, friends, caretakers, and colleagues) [4, 12,13,14]. This burden is due to the severity of their illness [13, 15, 16] and a range of healthcare barriers, including delayed times to referral, diagnosis, and treatment, among others [12, 17, 18]. Furthermore, their lives are often disrupted by debilitating symptoms, associated flare-ups, and comorbid EAD-associated conditions that require regular visits to the emergency department, hospital admissions, and a ‘cycling’ between multiple healthcare professionals (HCPs) [6, 13, 15, 19].

In many instances, these patient barriers and challenges stem from poor recognition of EADs by HCPs [12, 14, 20,21,22], which often leads to delays in receiving an accurate diagnosis, accessing specialist care, and receiving effective and safe treatments for the condition [12, 13, 19]. People with EADs often rely on long-term or intermittent oral corticosteroids (OCS), sometimes administered through multiple routes and in addition to other therapies, to suppress inflammatory activity and control their symptoms and disease flares [12, 13, 21]. Unfortunately, many commonly used treatments do not specifically target eosinophils despite these cells being a critical part of the underlying biological cause [6, 7]. Personalised treatment and earlier implementation of targeted safer anti-inflammatory treatment options, such as the new generation of eosinophil-targeting biologic therapies, may improve patient outcomes and could potentially avoid the adverse effects associated with OCS use [23,24,25,26,27]. As EAD biology and EAD patient needs become better understood among the scientific and healthcare communities and newer, innovative therapies become more widely available, there is a huge opportunity to improve patient outcomes [6, 7].

In 2018, a group of representatives from patient support groups, professional organisations, and the academic asthma treatment community developed a Patient Charter, which set forth six principles for the care of patients with severe asthma. That Charter outlined key patient expectations for management of their condition and described a basic standard of care for severe asthma according to the latest science and best practice understanding [28]. The 2018 Patient Charter was subsequently used as a guide by the Task Force to Improve Access to Better Care, when they developed the 2020 Global Quality Standard for managing severe asthma. As a complement to the 2018 Patient Charter, the 2020 Global Quality Standard was designed as both a guide and a stimulus for key stakeholders (e.g. governments, payers, policymakers) to instigate changes that improve early identification and diagnosis of severe asthma, prioritise timely referral to specialists, and optimise treatment and ongoing management [17]. Together, the 2018 Charter and the 2020 Quality Standard have provided a roadmap to clinically meaningful improvements in multiple aspects of care for patients with severe asthma [17, 28]. For example, since 2018, a cumulative OCS threshold of 1 g has been established in the literature and recommendations from the Global Initiative for Asthma (GINA) now reflect the adverse effects of OCS and suggest that, whenever possible, OCS should be avoided in managing asthma [29].

These two articles have highlighted how efforts to improve long-term patient outcomes must synergise the work of HCPs, health systems, policymakers, patient communities, and patient advocacy groups to optimise multiple aspects of care and treatment, including improved EAD diagnoses and timely access to specialist care. Furthermore, those efforts have been complemented by two recently established expert consensus definitions for clinical remission in asthma and severe asthma treatment super-response [30, 31]. These consensus definitions—both of which consist of generally similar criteria and describe roughly the same notion of disease remission in asthma—represent a defining moment in asthma management, and hopefully in the treatment of EADs in general, as they make it possible for clinicians to address important questions about treatment standards and improved disease management/awareness, with remission as the ultimate treatment goal.

An example of the progress that can result from consensus groups and use of the Delphi approach occurred in the late 1980s with the Rome group. The Rome group was established to answer difficult questions about a group of gastrointestinal disorders through the Delphi approach. This group ultimately developed the first diagnostic guidelines for irritable bowel syndrome in 1989 and it was the starting point for consensus-based criteria that have subsequently been established for a multitude of functional gastrointestinal diseases [32, 33]. Indeed, as the Rome group was very successful in making progress in gastrointestinal disease, our hope is that the recent progress in the field of severe asthma can become the foundation for the formation of an international working group with a common steering committee that can oversee disease specific sub-committees to drive, develop, and implement focused treatment recommendations for individual EADs. This article is based on principles that were debated and refined over a series of virtual discussions  and does not contain any new studies with human participants or animals performed by any of the authors.

Charter Purpose

To support this call to action, we—a group of leading patient advocacy groups and treating clinicians—present this charter to (1) outline key rights that we fervently believe patients should expect from the management of their condition(s) and (2) set out a basic standard of care to improve health outcomes for people affected by these life-altering and sometimes fatal diseases. It aims to unite the clinical community with the advocacy communities, which support people with EADs, by setting out clear actions that can improve patient care. This charter has been developed in line with the latest science and best practice understanding. It aims to inspire policymakers and healthcare decision-makers around the world to act to reform healthcare practices for people with EADs.

What Do All Individuals with EADs Deserve from Their Care?

Principle 1: People with EADs, Their Caretakers, HCPs, and the Public Must Have Greater Awareness and Education about EADs

Degrees of EAD awareness vary among HCPs, payers, and patients. This is due to the rarity of some of these conditions and the highly specialised and complex nature of EADs, including their heterogeneous clinical presentation, which can drive patients to visit multiple different clinical subspecialty providers who may not understand the potential impacts of the condition on other organ systems [34]. Furthermore, those in these groups, including HCPs, payers, and patients, frequently lack an understanding that eosinophils contribute to many aspects of these disorders (e.g. eosinophil immune dysfunction) and their effects on patients, healthcare systems, and HCPs across myriad clinical specialties [12].

Global professional societies for clinical subspecialities involved in EAD care and treatment, as well as guidelines for EAD clinical management, do exist for some conditions; however, expertise and guidance are not always used in regional or national approaches to disease management [19, 20, 35]. Furthermore, given that some clinical subspecialities are further divided into multiple specialised subdivisions, it can be challenging to find specialists who are knowledgeable about specific EADs. Since 2008, important steps have been taken to identify and define subsets of EADs by classifying the specific conditions, including the introduction of the first International Classification of Disease (ICD) codes for several EADs, including eosinophilic gastritis (EG; 535.70, now K52.81 in ICD-10), eosinophilic gastroenteritis (558.41, now K52.81 in ICD-10), and eosinophilic colitis (558.42, now K52.82 in ICD-10) [36, 37]. As of 2020, additional ICD codes for other subsets of EADs (eosinophilic esophagitis, ICD-10 code: K20.0) have been introduced thanks to collaborative efforts between patient associations and expert clinicians [37].

Targeted, tailored education and awareness programmes are necessary for HCPs in both primary and secondary care to enable a timely diagnosis and access to appropriate care. For primary care, educational programmes should emphasise conditions that may be driven by eosinophils; they should also describe symptoms and/or laboratory findings that may be associated with persistent eosinophilia and disease manifestations, some of which may not correlate with symptoms (e.g. elevated liver enzymes or occult cardiac involvement, which is suspected based on elevated troponin in the total absence of symptoms) and which may indicate the need for referral to appropriate specialists who can more conclusively diagnose and properly treat the disease [6, 7]. For HCPs in secondary care, messages should focus on providing an accurate diagnosis, using modern diagnostic tools, consulting with other subspecialties to evaluate other involved organ systems, and considering steroid-sparing treatment options, which may enable a more targeted approach to treating the underlying EID [7, 20, 21, 38]. Where clinical guidelines currently exist, national HCP groups must support increased awareness and adoption of these guidelines into national best practices. Furthermore, these efforts should be supported by appropriate funding for education and skills development to ensure continued medical education for all HCPs involved with the diagnosis, treatment, and long-term management of people with EADs. This medical education should be introduced across a range of specialities, including haematology, allergy, pulmonary, cardiology, gastroenterology, and primary care, where patients with EADs commonly enter the healthcare system.

Currently, little patient guidance exists about where to find and access educational materials and other helpful resources after diagnosis of an EAD. As such, better provision of accurate and relevant information is necessary to support people with EADs to manage their conditions. For example, it is critical to empower patients and their support network with sufficient resources to make the best use of appointments with their clinicians so that they can play an active and informed role in treatment decisions and management of their condition [38]. For EADs, this informed decision-making requires a basic understanding of how EID is involved in the pathology of their specific condition. Comprehensive educational resources and tools need to be updated as our understanding of EADs evolves and should be made readily accessible to people with presumptive or newly diagnosed EADs.

While these should offer baseline, foundational information on the role of eosinophils across the broad range of all EADs, EAD-specific materials reflecting unique patient challenges for the different illnesses (e.g. the impact of diet in gastrointestinal EADs), diagnostic processes, and potential treatments for each disease must also be accessible. These resources should be made available through their HCPs or delivered through better use of targeted digital and social campaigns to reach specific audiences, utilising best practices from other disease areas. Moreover, search engine optimisation should also be considered to ensure digital sources of information are easily accessible to patients.

In addition to the optimised delivery of educational resources described above, patient advocacy groups will continue to be a critical resource for patients and their support network [37, 39, 40]. Coupled with these improvements in HCP and patient education, we recognise that there is also a need for wider public awareness about the prevalence and burden of EADs, especially with respect to their impacts on patient HRQoL. Greater public awareness about EADs will help patients and providers recognise symptoms that warrant further evaluation, thereby reducing underdiagnosis, time to diagnosis, and the social and professional withdrawal that is common with certain EADs, which will drive further improvements in patient care. Indeed, increased public awareness of EADs will also improve the success of attempts by patient advocacy groups and others to obtain better financial coverage for long-term treatment and care of these conditions.

Principle 2: People with EADs Must Receive a Timely, Accurate Diagnosis

A prompt, accurate diagnosis is the foundation of effective care. Unfortunately, the patient journey from the onset of symptoms to EAD diagnosis can take many years, depending on the specific disease [41]. Patient surveys in EGIDs have shown that some patients received a diagnosis late in life, although the time varies depending on the specific EGID [19]. In terms of EADs in general, an initial diagnosis may occur in primary care (e.g. for conditions such as atopic dermatitis or asthma) [42]; however, given the often rare and complex nature of certain EADs, a formal diagnosis usually requires more in-depth assessments (e.g. imaging, bronchoscopy, or endoscopy with biopsies) after referral to a specialist [34]. Indeed, due to poor EAD recognition, patients with these conditions may not seek care, and when they do, they are frequently referred to several HCPs, leading to significant delays in accessing the specialist care they require [16, 19].

figure b

Patients who present to primary care physicians with clinical features consistent with an EAD should receive a basic workup, including a blood eosinophil count (appreciating that it is not always elevated in many EADs, including severe asthma and eosinophilic esophagitis, among others), and should be referred to a relevant specialist if the clinical picture is consistent with an EAD. Since consideration of an EAD in the differential diagnosis is critical to standardising this basic workup, greater awareness and targeted education are needed for HCPs about the conditions that are driven primarily by eosinophilic inflammation (see Principle 1). Clear referral guidelines, referral criteria, and the identification of recognised experts in different countries with access to clear and up-to-date diagnostic modalities and treatment options are also necessary to enable timely and appropriate referrals [19]. This is particularly important for gastrointestinal EADs where, aside from HES with gastrointestinal involvement and eosinophilic esophagitis (EoE), diagnostic criteria are not well established. These standards should be coupled with appropriate patient screener questionnaires to assist in establishing an accurate diagnosis, as people with EADs may not always report the full burden of their condition or may not be aware of the potential symptoms associated with elevated eosinophil counts. Moreover, efforts to develop less invasive means of diagnosing and following disease activity in EADs should be a priority, as this would improve the time to and accuracy of diagnoses while reducing patient burden (e.g. repeated invasive procedures).

Many other conditions have clearly defined “waiting time targets” to ensure rapid diagnosis and treatment. Establishing similar targets and referral pathways for EADs would enable patients to receive a more timely, accurate diagnosis. Indeed, streamlining the patient journey is key to improving long-term outcomes and HRQoL for patients with EADs [38].

Principle 3: All People with EADs Must Have Access to an Appropriate Multidisciplinary Team, When Necessary

The diagnosis, management, and treatment of many EADs, including severe eosinophilic asthma, HES, EoE, and EGPA, require input from a multidisciplinary team (MDT) to confirm the diagnosis and determine the best treatment approach on a case-by-case basis [12, 20, 21].

figure c

Many barriers can limit patient access to appropriate specialist care, including socioeconomic status, language, education, care availability, and geography [12, 13, 19]. Given the rarity of some of these conditions, expertise is often lacking in certain regions, which can mean patients either go without appropriate care or must travel long distances to access specialists. These drawbacks may influence patients’ decisions about treatment choices given the potential costs, including time away from work, school, or family responsibilities. Patients with EADs may also experience physical limitations because of their symptoms, which can prevent them from being too far from home for extended periods of time. Additionally, in countries with insurance-based healthcare systems, like the US, patients with EADs may not be able to access specialist care if they are uninsured or their insurance does not cover the visit [12].

In addition to the above barriers against access to appropriate care, patients with EADs may have more than one EAD, additional comorbidities, and/or complex, multisystem expression of a single EAD (e.g. EGPA or HES), and they may often see multiple clinicians who treat each disease or clinical manifestation independently, rather than providing the holistic approach that is frequently needed [13, 36, 44]. This lack of coordinated care can create an inadequate and siloed treatment approach that fails to achieve the best possible outcomes for the patient. It also exacerbates the geographic challenges in many cases: a patient with both severe eosinophilic asthma and EoE may need to see a pulmonologist in one location hours from their home and a gastroenterologist similarly far away on a different day and time.

We recommend that people with EADs be managed by multidisciplinary teams (MDTs) with access to appropriate resources and personnel [38]. For instance, in oncology, the MDT approach emerged in the mid-1980s and has been shown to result in better treatment adherence and tolerance, reduction in long-term side effects of treatments, improved quality of life, and, ultimately, improved outcomes and survival [45]. Access to comprehensive MDTs for patients with other conditions, including EADs, has been lacking. This care planning should include an EAD coordinator (e.g. a nurse specialist), with an understanding of all of the relevant disciplines and HCPs trained in the EAD spectrum, who can bring together the relevant specialisms required to treat a person with an EAD. As a dedicated EAD coordinator can be costly, financial support must be provided to cover the costs of this resource, which can ultimately reduce healthcare burden/costs and improve patient outcomes. Expert care centres with these resources should be identified and validated at the regional and national levels. Circumstances will differ from patient to patient, so care must be personalised to focus on each individual’s priorities, which can be accomplished by using a shared decision-making model [38].

New models of care are needed to make better use of regional expertise and reduce the geographic, travel-related, and socioeconomic barriers that sometimes prevent access to care. This can be achieved through better use of technology, such as telemedicine/video consultations, disease management smartphone apps, and new home diagnostic kits or biomarker monitoring. These initiatives have the potential to increase access to specialist MDTs and, in many cases, eliminate the need for travel [38]. Local leadership should be established to champion improved care for people with EADs. Such leadership could come from HCPs or health system leaders, who would be responsible for ensuring care standards are maintained.

Coupled with the recommendations above, accessible and readily available information is necessary to help patients and their support network find specialist care. This is an area where patient advocacy groups can help patients identify and connect with specialist MDTs. An online specialist care finder, like the global care finders provided by the American Partnership for Eosinophilic Disorders (APFED) and EOS Network, could be made available on public health agency websites or patient advocacy group websites in each country to make this connection possible [46, 47].

Principle 4: People with EADs Must Have Access to Safe and Effective Treatment Options Without Unnecessary Regulatory Delays

Poor understanding of the central role of eosinophilic inflammation in many of the EADs can result in suboptimal treatment choices and excessive OCS use [13, 21]. Patients are often reliant on OCS or even multiple-use OCS in those with comorbid EADs, which are associated with life-altering acute and chronic adverse effects [23, 25, 27]. Despite the advent of targeted, biological therapies, access to these new therapies can be limited, and a ‘fail-first’ approach to treatment can make these innovative treatments inaccessible to patients in a timely manner. Moreover, a lack of payer knowledge about the burden of EADs, the latest evidence, the latest studies, and the acceptance of smaller trials and data sets limits their understanding of these conditions and thus their motivation and willingness to assess innovative medicines properly. In some cases, patients may turn to self-management of their conditions to alleviate their symptoms, often through lifestyle modifications and restricted diets and sometimes through self-medication, which may include inappropriate and potentially dangerous self-adjustments to OCS dosing.

The approach to the treatment of EADs across and within countries is not always consistent; even for more common EADs, such as eosinophilic asthma, a failure to measure and recognise an elevated blood eosinophil count can limit the appropriate treatment options available to patients [48]. Inexpensive, noninvasive diagnostic tools and disease biomarkers, such as the blood eosinophil count and exhaled nitric oxide testing (FeNO) for severe eosinophilic asthma, along with more invasive tests including tissue biopsies, should be readily available to diagnose and identify the most appropriate treatment for people with EADs.

Robust global treatment guidelines need to be developed or updated to reflect new treatment options, which address the underlying mechanisms of disease and ensure patients are offered the right treatment, at the right time, with the fewest possible adverse effects. Specifically, efforts should be taken to reduce and avoid the use of OCS when safe and effective alternatives are available. People with EADs should also receive regular treatment evaluations to ensure their conditions are managed appropriately and treatment is optimised. These evaluations could be accomplished through innovative methods that have become more mainstream due to the COVID-19 (coronavirus disease) pandemic, such as, for example, better use of telemedicine [49]. Updated guidelines should also be shared widely amongst HCPs involved with the treatment of people with EADs to ensure consistent and coordinated care.

Patients should also receive relevant information about their EAD from their HCP and healthcare system and/or through patient advocacy groups. This information should be in a simple and clear format to support increased understanding of the roles of eosinophils as a critical component of inflammation in EADs, as well as the treatment and management options available to support shared decision-making [38]. All patients with an EAD should have a dedicated ‘action plan’ to help with the self-management of their condition. Such plans should be developed in partnership with their MDT and based on up-to-date information from relevant resources (such as EAD-specific patient advocacy groups) and in coordination with family and loved ones who support their patient journey.


EADs place a significant burden on the lives of millions of people worldwide with these diseases, as well as on their healthcare systems. A number of clear steps can be taken to help reduce this burden and improve patient outcomes. Unfortunately, the rarity of some of these conditions means EADs are often poorly understood and suboptimally treated. Even for the more common conditions like asthma and atopic dermatitis, management guidelines are infrequently followed in clinical practice. As evidenced by progress that was made across multiple functional gastrointestinal disorders over nearly 3 decades by the Rome group, and much more recently in the field of severe asthma, to optimise patient care we must establish disease-specific, best practice recommendations and review or revise current care practices for the diagnosis and management of all EADs [17, 28, 30,31,32,33]. This includes engaging stakeholders at multiple levels of healthcare systems (e.g. HCPs, policymakers, payers, patient communities, patient advocacy groups) and experts at both national and international levels. Furthermore, there is an urgent need for increased recognition and understanding of EADs and the role of eosinophilic inflammation in EAD pathogenesis. Such initiatives will better support people with EADs to receive accurate, timely diagnoses and enable them to access state-of-the-art care and treatment in an appropriate setting; indeed, they will also lead to further development of other new therapies that are tailored to each patient’s condition/phenotype (i.e. personalised medicine).

The principles we have set out in the charter demonstrate the core elements of quality care that people with EADs must receive. We urge healthcare providers, health systems, and policymakers around the world to swiftly implement these principles and ensure that the current advancements and latest approaches in science reach the patients who need them most.