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PubMed This is a summary of 20 peer-reviewed journal articles Updated

The Clinical Phases of EGPA: A Roadmap for Patients

At a Glance

EGPA typically progresses through three clinical phases: an allergic phase marked by severe adult-onset asthma, an eosinophilic phase involving high white blood cell counts and organ inflammation, and a vasculitic phase causing blood vessel damage and nerve issues.

Understanding Eosinophilic Granulomatosis with Polyangiitis (EGPA) often means looking back at your health history to see how different symptoms fit together. Historically, doctors have described EGPA as moving through three distinct clinical phases [1][2]. However, it is important to know that these stages do not always follow a strict order; you might skip a phase, cycle back to an earlier one, or experience symptoms from all three at the same time [3][4].

Phase 1: The Allergic (Prodromal) Phase

For many, the journey begins years before a formal diagnosis. This phase is characterized by allergic-type inflammation that primarily affects the airways [5][6].

  • Adult-Onset Asthma: This is often the most prominent symptom. Unlike childhood asthma, this typically develops in your 30s or 40s and can be refractory, meaning it is very difficult to control even with high doses of steroids or multiple inhalers [7][8].
  • Sinonasal Disease: Chronic sinusitis (sinus inflammation) and the growth of nasal polyps (soft, noncancerous growths in the nasal passages) are very common [9][10].
  • Allergic Rhinitis: You may experience persistent “hay fever” symptoms, such as a runny nose, congestion, and sneezing [1].

Phase 2: The Eosinophilic Phase

In this stage, the disease becomes more systemic. Your body produces an excessive number of eosinophils—specialized white blood cells—which begin to infiltrate and damage various organs [11][2]. You can read more about how these cells cause damage in The Biology of EGPA.

  • Eosinophilic Infiltration: These cells can gather in the lungs (causing coughing or shortness of breath), the digestive tract (causing abdominal pain, nausea, or diarrhea), and even the heart [12][4].
  • Constitutional Symptoms: Many patients begin to feel generally unwell, experiencing unexplained fevers, night sweats, significant fatigue, and weight loss [12][13].
  • High Blood Counts: A blood test during this phase will usually show a very high absolute eosinophil count (AEC) [14][15].

Phase 3: The Vasculitic Phase

This is the “active” vasculitis stage, where small-to-medium blood vessels become inflamed, potentially cutting off oxygen and nutrients to tissues [16][11]. While reaching this phase can sound daunting, it is actually the point where the disease’s true nature becomes clear, often finally leading to an accurate diagnosis and effective treatment.

  • Mononeuritis Multiplex: This is a hallmark symptom where specific nerves are damaged. It often feels like sudden numbness, tingling, or “pins and needles” in a specific hand or foot. It can progress to foot drop or wrist drop, where you lose the ability to lift your foot or hand [17][18].
  • Skin Manifestations: You may notice purpura (purple or red spots that look like small bruises or a rash), especially on the legs, or small nodules (lumps) under the skin [15][19].
  • Organ Damage: This phase can involve the kidneys (leading to high blood pressure or issues filtering waste) and the heart, requiring careful monitoring by your medical team [19][20].

Common questions in this guide

What is the allergic phase of EGPA?
The allergic phase is often the first stage of EGPA, beginning years before a formal diagnosis. It is primarily characterized by severe, adult-onset asthma that is difficult to control, alongside chronic sinus issues and nasal polyps.
What happens during the eosinophilic phase of EGPA?
In the eosinophilic phase, the body produces an excessive amount of eosinophils, a type of white blood cell. These cells can build up in and inflame organs such as the lungs, heart, and digestive tract, leading to general symptoms like fever, fatigue, and weight loss.
What are the symptoms of the vasculitic phase of EGPA?
The vasculitic phase is marked by active inflammation of small-to-medium blood vessels. This restricts blood flow and can cause nerve damage known as mononeuritis multiplex, skin rashes called purpura, and potential damage to the heart or kidneys.
Can I skip a phase of EGPA or have them out of order?
Yes, the three phases of EGPA do not always follow a strict chronological order. Patients may skip a phase, cycle back to an earlier one, or experience symptoms from multiple stages simultaneously.
Is nerve pain or numbness a symptom of EGPA?
Yes, sudden numbness, tingling, or weakness in a specific hand or foot can occur during the vasculitic phase of EGPA. This specific type of nerve damage is called mononeuritis multiplex and can sometimes progress to foot drop or wrist drop.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Which of the three phases best describes my current symptoms, or do I have symptoms from multiple phases at once?
  2. 2.Is my asthma considered 'refractory,' and how does that influence our choice of treatment for the prodromal phase?
  3. 3.What does my absolute eosinophil count tell you about the risk of organ infiltration in my lungs or heart?
  4. 4.Are my neurological symptoms, like numbness or weakness, a sign of mononeuritis multiplex?
  5. 5.Since renal involvement is possible in the vasculitic phase, how often should we be checking my kidney function?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (20)
  1. 1

    Otologic and Rhinologic Manifestations of Eosinophilic Granulomatosis with Polyangiitis.

    Nakamaru Y, Takagi D, Suzuki M, et al.

    Audiology & neuro-otology 2016; (21(1)):45-53 doi:10.1159/000442040.

    PMID: 26812614
  2. 2

    [Clinical analysis of 43 patients with eosinophilic granulomatosis with polyangiitis].

    Li J, Zhang L, Zhao W, et al.

    Zhonghua yi xue za zhi 2016; (96(10)):787-91 doi:10.3760/cma.j.issn.0376-2491.2016.10.008.

    PMID: 27055639
  3. 3

    Primary care physicians play a crucial role in diagnosing and managing rare eosinophilic diseases: HES and EGPA.

    Shum M, Gewurz-Singer O, Silver J, Akuthota P

    Frontiers in medicine 2025; (12()):1568770 doi:10.3389/fmed.2025.1568770.

    PMID: 40630493
  4. 4

    Initial Hemorrhagic Pericardial Effusion Evolving Into Perimyocarditis: An Atypical Early Presentation of Eosinophilic Granulomatosis With Polyangiitis.

    Almatrafi SA, Quqandi SM, Ismail SJ, Alghamdi KA

    Cureus 2025; (17(7)):e88155 doi:10.7759/cureus.88155.

    PMID: 40821336
  5. 5

    A case of cardiac arrest and spontaneous renal hemorrhage in a male patient with persistent eosinophilia: highlighting the importance of early diagnosis of eosinophilic granulomatosis with polyangiitis.

    Lin J, Wang R, Zhu Y, et al.

    Journal of Zhejiang University. Science. B 2025; (26(7)):708-712 doi:10.1631/jzus.B2300940.

    PMID: 40722247
  6. 6

    A Case of Eosinophilic Granulomatosis with Polyangiitis Presenting with Mononeuritis Multiplex.

    Alam MA, Hossain MI, Khan AH, Arafat SM

    Current rheumatology reviews 2022; (18(4)):368-372 doi:10.2174/1573397118666220330005431.

    PMID: 35352664
  7. 7

    The diagnosis of eosinophilic granulomatosis with polyangiitis has been 'masked' by asthma: a case report.

    Xie H, Zhang X, Zhang J, et al.

    AME case reports 2025; (9()):31 doi:10.21037/acr-24-79.

    PMID: 39866258
  8. 8

    Clinical, Biomarker, and Radiological Progression from Asthma to Systemic Eosinophilic Granulomatosis with Polyangiitis: A Retrospective Cohort Study.

    Lu C, Ou C, Deng Y, et al.

    Journal of asthma and allergy 2025; (18()):1615-1626 doi:10.2147/JAA.S542255.

    PMID: 41244373
  9. 9

    A Rare Case of Eosinophilic Granulomatosis with Polyangiitis Following Development of Central Diabetes Insipidus: A Case Report and Literature Review.

    Kosaka T, Yamamoto S, Yasugi N, et al.

    Internal medicine (Tokyo, Japan) 2026; (65(1)):149-155 doi:10.2169/internalmedicine.5558-25.

    PMID: 40467512
  10. 10

    [A Rare Cause of a Eosinophilic Lung Disease].

    Stolpe C, Tannapfel A

    Pneumologie (Stuttgart, Germany) 2021; (75(3)):221-225 doi:10.1055/a-1220-7149.

    PMID: 32927489
  11. 11

    A Rare Presentation of Bilateral Foot Drop in Anti-neutrophil Cytoplasmic Antibody (ANCA)-Negative Eosinophilic Granulomatosis With Polyangiitis (Churg-Strauss Syndrome): A Diagnostic Challenge.

    Isar MM, Al-Banna M, Hulo MG, et al.

    Cureus 2025; (17(6)):e86765 doi:10.7759/cureus.86765.

    PMID: 40718238
  12. 12

    Looking Beyond Pneumonia and Asthma in India: An Interesting Case of Churg-Strauss Syndrome.

    Kumar A, Gaba M, Kumar N, Kumar A

    Cureus 2024; (16(8)):e66416 doi:10.7759/cureus.66416.

    PMID: 39246977
  13. 13

    A rare case of eosinophilic granulomatosis with polyangiitis complicated with progressive pericardial effusion.

    Arinaga T, Komaki T, Miura SI, et al.

    Journal of cardiology cases 2017; (15(5)):163-166 doi:10.1016/j.jccase.2017.01.001.

    PMID: 30279769
  14. 14

    Clinical implications of peripheral eosinophil count at diagnosis in patients newly diagnosed with microscopic polyangiitis and granulomatosis with polyangiitis.

    Ha JW, Ahn SS, Song JJ, et al.

    Arthritis research & therapy 2023; (25(1)):245 doi:10.1186/s13075-023-03233-1.

    PMID: 38102670
  15. 15

    Immunological Markers Associated with Skin Manifestations of EGPA.

    Brunetto S, Buta F, Gangemi S, Ricciardi L

    International journal of molecular sciences 2025; (26(15)) doi:10.3390/ijms26157472.

    PMID: 40806600
  16. 16

    When inflammation is not just inflammation-A review of systemic diseases of the nose and sinuses part 2: Granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis.

    Cler SJ, Ogden MA, Farrell NF, et al.

    American journal of otolaryngology 2024; (45(3)):104207 doi:10.1016/j.amjoto.2023.104207.

    PMID: 38176206
  17. 17

    Severe mononeuritis multiplex in a patient with eosinophilic granulomatosis with polyangiitis.

    Kalinova D, Kukushev G, Kolarov Z, Rashkov R

    Reumatologia 2019; (57(5)):288-291 doi:10.5114/reum.2019.89522.

    PMID: 31844342
  18. 18

    Churg-Strauss Syndrome or Eosinophilic Granulomatosis with Polyangiitis: Exuberant Classic Clinical Picture of a Rare Disease.

    Mukamal LV, Sodré CT, Prata LB, et al.

    Case reports in dermatology 2018; (10(2)):175-181 doi:10.1159/000489162.

    PMID: 30057533
  19. 19

    Cardiac Eosinophilic Masses in Man With Eosinophilic Granulomatosis With Polyangiitis.

    Amidi O, Siebert VRJ, Allison J, Hamzeh IR

    Texas Heart Institute journal 2020; (47(4)):337-338 doi:10.14503/THIJ-19-7084.

    PMID: 33472240
  20. 20

    A discussion on a suspected case with EGPA after maintenance hemodialysis for 5 years and related literature analysis: A case report.

    Zhao L, Zhang C

    Medicine 2024; (103(38)):e39856 doi:10.1097/MD.0000000000039856.

    PMID: 39312300

This page provides an educational overview of EGPA clinical phases. Always consult your medical team to properly evaluate your specific symptoms, organ involvement, and disease stage.

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