Pleural Involvement in EGPA
Yes, EGPA can affect the pleura, but pleural effusions are an uncommon manifestation of the disease, occurring much less frequently than other pulmonary manifestations such as lung infiltrates.
Frequency of Pleural Involvement
Pleural effusions are rare in EGPA and are not listed among the common organ manifestations in current evidence-based guidelines. 1 The 2023 Nature Reviews Rheumatology guideline specifically identifies lung infiltrates as common (occurring in 40-50% of patients), but does not mention pleural involvement among the typical clinical features. 1
Common Pulmonary Manifestations vs. Pleural Disease
The typical pulmonary involvement in EGPA includes:
- Lung infiltrates occur in 40-50% of patients and are often multiple, migratory, and responsive to systemic glucocorticoids 1
- Asthma is present in >90% of EGPA patients, representing the most common respiratory manifestation 2, 3
- Bilateral pulmonary infiltrates are characteristic, occurring in approximately 86% of cases 3
In contrast, pleural effusions are documented as "an uncommon manifestation of EGPA" in case reports. 4 When pleural effusions do occur, they may present alongside other pulmonary findings such as nodules and infiltrates. 4
Clinical Context
Cardiac involvement (myocarditis and pericarditis) is explicitly mentioned as an organ manifestation in EGPA, 1 and pericarditis could theoretically lead to pericardial effusions. However, isolated pleural disease is not emphasized in the major guidelines as a typical feature.
When evaluating a patient with suspected EGPA and pleural effusions, clinicians should consider that this represents an atypical presentation and ensure thorough evaluation for the more common manifestations including asthma, peripheral eosinophilia, lung infiltrates, peripheral neuropathy (50-70%), skin lesions, and cardiac involvement. 1, 2
Diagnostic Implications
The absence of pleural involvement from the ACR classification criteria (which include asthma, eosinophilia >10%, neuropathy, non-fixed lung infiltrates, paranasal sinus abnormalities, and histological evidence of extravascular eosinophils) further underscores that pleural disease is not a defining or common feature of EGPA. 1