Wat Zijn Churg-Strauss Huidziekten?

Other names

People may also use these other terms for the condition:

• Churg-Strauss vasculitis
• allergic granulomatosis
• allergic granulomatosis and angiitis
• allergic angiitis and granulomatosis

Because Churg-Strauss syndrome can target different organs within the body, symptoms can vary widely from person to person. The condition often has three distinct phases, though this does not happen in every case.

Many symptoms vary, but asthma commonly occurs, affecting 96% of people with Churg-Strauss syndrome.

Around half of people also experience skin conditions, including :

• purplish skin lesions, such as purpura, petechiae, and ecchymosis
• skin nodules, commonly on the scalp or the elbows or other extremities

StatPearls [Internet].

Rebanta K. Chakraborty , Narothama R. Aeddula .

Authors

Affiliations

Last Update: August 25, 2024 .

Although EGPA is classified as an ANCA-associated vasculitis, ANCA is positive in only 30% to 40% of cases, making diagnosis challenging. The dichotomy of presentations and the variability of symptoms make diagnosis particularly challenging. Similarly, treatment responses can be inconsistent, and the recommendations for managing EGPA differ from those for other AAVs, such as granulomatosis with polyangiitis and microscopic polyangiitis. Clinical recognition of multisystem involvement, especially in patients with eosinophilic asthma, is key to diagnosis. The management of EGPA also differs from other AAVs, requiring tailored treatment strategies. This activity reviews the presentation, evaluation, and management of EGPA, highlighting the crucial role of an interprofessional healthcare team in optimizing patient care, particularly given the variability in symptoms and treatment responses.

Identify the key clinical features of eosinophilic granulomatosis with polyangiitis, including asthma, rhinosinusitis, and peripheral eosinophilia, to ensure early diagnosis.

Implement tailored treatment strategies for eosinophilic granulomatosis with polyangiitis, considering both the eosinophilic phenotype and antineutrophil cytoplasmic autoantibody–associated phenotype.

Select appropriate immunosuppressive therapies based on the severity of eosinophilic granulomatosis with polyangiitis and the presence of poor prognostic factors.

Collaborate with an interprofessional healthcare team to optimize the management of eosinophilic granulomatosis with polyangiitis, ensuring a comprehensive approach to patient care.

Diagnostic tests

Blood tests – Blood tests will show high levels of Eosinophil white blood cells in patients with active EGPA. Blood tests may also show damage to the kidneys, or may show a type of antibody related to vasculitis (ANCA).

Chest X-ray – People with active EGPA may have patches of vasculitic damage where eosinophils invade and damage the lung tissue (infiltrates) that may be visible on a chest x-ray.

Lung function – All patients diagnosed with EGPA have asthma, and this will almost always be shown through spirometry (breathing tests) that show an inability to breathe out a quickly as should be possible which improves when given inhaled treatment.

Biopsy – If biopsies (tissue samples) are taken, these may show high numbers of eosinophils, collections of immune cells (known as a granuloma), and damage to blood vessels cause by immune cells (vasculitis). Biopsies may be taken from any affected tissues (lung, nerves, skin, kidneys etc.) and are the most conclusive way of diagnosing the disease.

Bronchoscopic lavage – Camera tests may be performed to “wash out” areas of the lung. This fluid can show high numbers of eosinophils and may have blood in too. This test is most useful in making sure that other problems such as infection or cancers are not present.

Heart tests – People with EGPA can have damage to their heart, and so a heart tracing (electrocardiogram – ECG) and/or ultrasound test (echocardiogram) are often performed. This may be followed up with further tests where abnormal areas are found.

Epidemiology

In contrast to certain small vessel vasculitides, such as immunoglobulin A (IgA) vasculitis and Kawasaki disease, with a preponderance in childhood, AAV is rare in children. However, regardless of age, both adult and childhood EGPA present with highly elevated IgE and eosinophil levels. About 40% of adults with EGPA have a positive ANCA, whereas 25% of children are seropositive for this.

The pathogenesis and clinical phenotype of EGPA follow a dichotomy of either eosinophil-mediated damage or ANCA-induced endothelial injury.

Eosinophils

An initial Th2-mediated immune response triggers the margination of eosinophils. Their presence in active disease likely results from increased synthesis, enhanced extravasation, and prolonged survival in target tissues. IL-3 and IL-5, produced by Th2 lymphocytes, are key regulators of eosinophil maturation, release, and survival in the bloodstream. Serum levels of IL-5 consistently correlate with disease activity and decrease with the initiation of immunosuppressive therapy.[19][20][21]

IL-5 mediates eosinophilic tissue infiltration, as shown by the persistence of tissue major basic protein despite therapy with mepolizumab, which leads to complete downregulation of IL-5 titers. IL-4 and IL-13, other potent cytokines associated with the Th2 immune response, may also play a significant role in tissue infiltration and degranulation of eosinophils.[23] Peripheral blood eosinophils in EGPA exhibit activation markers such as CD69 and CD25, along with elevated serum levels of IL-5 and ECP.[24][25]

Antineutrophil cytoplasmic autoantibody

Infusion of MPO-ANCA in wild-type and Rag2 knockout mice resulted in severe necrotizing and crescentic glomerulonephritis.[26] The hypothesis of two clinical subsets in EGPA has been further supported by recent findings showing an increased frequency of HLA-DRB4 in ANCA-positive EGPA patients. Additionally, emerging evidence suggests that Th17 lymphocytes play a role in the occurrence and maintenance of the vasculitis response, particularly concerning the balance between Th17 and Treg cells.[27] However, endothelial injury in AAV is primarily mediated by neutrophils through the generation of reactive oxygen species and proteolytic enzymes from cytoplasmic granules.[28][29][30]