What Is It, Causes, Diagnosis, Treatment, and More
Author:Michail Mavrogiannis, MD
Editors:Alyssa Haag,Emily Miao, PharmD
What is Churg-Strauss syndrome?
Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as Churg-Strauss syndrome, belongs to a group of autoimmune rare diseases that cause vasculitis (i.e., inflammation of the blood vessels), which is often not apparent in the initial phases of the disease. Churg-Strauss syndrome mainly affects small and medium-sized systemic blood vessels, such as arterioles, capillaries, venules, and coronary arteries. It is characterized by the presence of eosinophilia, or increased levels of eosinophils, which are a subtype of white blood cells typically involved in parasitic infections and cancer; evidence of granulomatous necrotizing vasculitis, which is characterized by inflammation of the blood vessels, signs of tissue death (or necrosis), and collections of immune cells in or near the vessel wall; and abnormal lesions in the lungs that may mimic pneumonia. Although the lung is the most commonly involved organ, Churg-Strauss syndrome can affect any organ system, including the skin, cardiovascular system, gastrointestinal system, kidneys, and central nervous system. A hallmark of the disease is its association with asthma and rhinosinusitis, which is the inflammation of the nasal cavity and the paranasal sinuses.
How common is Churg-Strauss syndrome?
Churg-Strauss syndrome is a rare condition, affecting approximately 11 to 14 individuals per million people worldwide. While individuals of all ages can present with the disease, the average age of onset is 38 to 54 years of age. Churg-Strauss syndrome, in contrast to other vasculitides, is extremely rare in children. However, children who are diagnosed with Churg-Strauss tend to experience a more aggressive course that typically involves the lungs and cardiovascular system. Mortality rates amongst children is substantially higher than that of adults with Churg-Strauss.
What causes Churg-Strauss syndrome?
The exact causes of Churg-Strauss syndrome are not clear; however, most cases are attributed to a combination of factors. As the disease is classified as an autoimmune disorder, the immune system plays a significant role in the development of Churg-Strauss. Antineutrophil cytoplasmic antibodies (ANCA), or antibodies against neutrophils, one of the subtypes of white blood cells, can oftentimes be elevated, though their exact role in Churg-Strauss syndrome development is unknown. Genetics and environmental factors (e.g., exposure to industrial solvents and infectious diseases) may also contribute to the development of the disease.
What are the symptoms of Churg-Strauss syndrome?
Patients with Churg-Strauss syndrome most commonly present with symptoms of asthma, such as shortness of breath, wheezing, and coughing, as well as symptoms of rhinosinusitis, which include face pain and nasal congestion. They may also experience non-specific symptoms, such as fever, fatigue, loss of appetite, and pain in their muscles and joints. Individuals may also develop neurological problems, especially peripheral neuropathy, which presents with numbness and tingling of the hands and feet. In addition to numbness and tingling, peripheral neuropathy may also include pain and weakness, and patients may present with wrist or foot drop. Gastrointestinal disturbances, such as abdominal pain and loss of appetite and skin lesions—including subcutaneous nodules and purpura—can also be present.
How is Churg-Strauss syndrome diagnosed?
Diagnosis usually relies on clinical presentation, blood tests, and imaging studies as there is no single test to confirm Churg-Strauss syndrome. Churg-Strauss may be suspected in a patient with asthma and peripheral neuropathy, along with a history of acute or chronic rhinosinusitis. On various blood tests, individuals with Churg-Strauss typically show increased eosinophils as well as increased ANCA autoantibodies. Imaging tests, specifically a chest X-ray or CT scan, can usually reveal abnormal lesions in the lungs that mimic pneumonia. Those lung lesions characteristically migrate, or move, from one place to another and may also come and go intermittently. In some cases, a tissue biopsy from affected tissues, such as the skin or nasal mucosa, may be ordered and can show an increased number of eosinophils.
How is Churg-Strauss syndrome treated?
Although there is no cure for Churg-Strauss syndrome, patients should seek medical advice in order to receive medications that can reduce inflammation and help manage their symptoms. The initial management typically includes medium to high doses of glucocorticoids (e.g., prednisone). Glucocorticoids reduce inflammation and the levels of eosinophils in tissues and blood vessels. Once remission has been attained, the dose of glucocorticoids is usually steadily lowered in order to limit the acute and long-term side effects. In most cases, they are eventually discontinued. If glucocorticoid-related toxicity occurs, or the disease remains unmanageable on glucocorticoids, individuals can be given other immunosuppressant medications, such as azathioprine, methotrexate, or cyclophosphamide. Additionally, individuals with severe symptoms of Churg-Strauss may receive a combination of glucocorticoids and immunosuppressant medications. Finally, individuals with Churg-Strauss that are refractory to other treatments may benefit from intravenous immune globulins (IVIG) or novel biologic agents, such as mepolizumab.
What are the most important facts to know about Churg-Strauss syndrome?
Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as Churg-Strauss syndrome, is a rare autoimmune vasculitis that affects small to medium-sized blood vessels. It is characterized by the presence of eosinophilia, increased ANCA levels, asthma, and rhinosinusitis. The exact cause is unknown, with both genetic and environmental factors contributing to the disease development. Individuals with Churg-Strauss typically present with symptoms of asthma, rhinosinusitis, non-specific symptoms (like fever and fatigue), peripheral neuropathy, gastrointestinal disturbances, and skin lesions (such as subcutaneous nodules and purpura). There is no specific test to confirm the diagnosis, and diagnosis is usually based on clinical findings, presence of eosinophilia, increased ANCA levels, imaging studies, and (less frequently) biopsy results from the affected tissues. There is no cure for Churg-Strauss syndrome and, thus, therapy is focused on managing symptoms and reducing inflammation. Individuals are typically treated with glucocorticoids, such as prednisone, or immunosuppressants, such as azathioprine. Refractory cases may benefit from a combination of glucocorticoids and immunosuppressants, IVIG, or novel biologic agents.
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Resources for research and reference
Bosch, X., Guilabert, A., Espinosa, G., & Mirapeix, E. (August 2007). Treatment of antineutrophil cytoplasmic antibody associated vasculitis: A systematic review. JAMA. 298 (6): 655–69. DOI: 10.1001/jama.298.6.655
Chakraborty, R.K. & Aeddula, N.R. (2021). In StatPearls. Retrieved June 1, 2021 from https://www.ncbi.nlm.nih.gov/books/NBK537099/
Hacking, C., Weerakkod, Y. et al. (n.d.). Eosinophilic granulomatosis with polyangiitis. In Radiopedia. Retrieved June 1, 2021 from https://radiopaedia.org/articles/eosinophilic-granulomatosis-with-polyangiitis?lang=gb
Jones, T. (2015). Churg-Strauss syndrome now renamed eosinophilic granulomatosis with polyangiitis (EGPA). In Vasculitis UK. Retrieved June 1, 2021 from https://www.vasculitis.org.uk/about-vasculitis/churg-strauss-syndromeStone, J.H. (2003). Churg-Strauss Syndrome. NORD Guide to Rare Disorders. Philadelphia, PA: Lippincott Williams & Wilkins.