Medical Care
Treatment decisions for eosinophilic granulomatosis with polyangiitis (EGPA) should be based on affected organ systems and the severity of the vasculitis. EGPA is typically a corticosteroid-responsive disease; hence, they are first-line therapeutic agents. EGPA may have an abrupt onset involving multiple organ systems and a relapsing and remitting course. The use of corticosteroids and cyclophosphamide in patients with severe manifestations has greatly improved survival rates and prognosis. [24, 25] Intravenous corticosteroids should be considered for patients with extensive disease. Dramatic responses to therapy may be observed, with improvement in eosinophilia counts, reduction of the erythrocyte sedimentation rate (ESR), and reduction in muscle enzyme levels within 1-2 weeks of the initiation of treatment. Corticosteroids may be tapered once clinical improvement occurs. Importantly, note that patients with EGPA-related neuropathy respond more slowly to treatment. Residual asthma or other symptoms may require the continuation of low-dose prednisone therapy. [10]
Cyclophosphamide should be initiated in severely ill patients who do not respond to initial therapy. Patients with life-threatening disease or those at risk of organ failure are potential candidates. The addition of cyclophosphamide appears to improve outcomes and reduces the incidence of relapses. For patients with systemic disease who are not at risk for major organ failure or death, methotrexate (MTX) may be given as a corticosteroid-sparing agent to reduce the cumulative dose. However, whether methotrexate reduces relapses remains questionable. [24] Other immunomodulatory medications include azathioprine (AZA) and mycophenolate mofetil, which may also be used as corticosteroid-sparing agents. AZA is best used for maintenance therapy rather than for induction of remission in refractory disease. Chlorambucil and plasma exchange have occasionally been used and are most effective when used in combination therapy. [23]
Agents that block tumor necrosis factor (TNF), such as infliximab and etanercept, have been used for a limited period in severe life-threatening cases. These agents, when combined with corticosteroids or other immunomodulatory agents, greatly increase the risk of infection due to immunosuppression. More data are needed to determine whether these drugs have a favorable risk-to-benefit ratio for use in EGPA patients. Another infrequently used therapy is recombinant interferon (IFN) alfa, which can be effective when given on a short-term basis in otherwise refractory cases. One anecdotal case report has described the use of rituximab in a patient with recalcitrant EGPA and another described the use of imatinib mesylate. [23, 26, 27, 28, 29]
Other studies have focused on the inhibition of interleukin 5 (IL-5) or the IL-5 receptor as a potential target for treatment in asthma and asthmatic conditions associated with eosinophilia such as EGPA. IL-5 is a cytokine involved in the regulation of eosinophils, including their maturation, activation, and survival. IL-5 levels have been found to be increased in EGPA patients. Promising anti–IL-5 drugs include mepolizumab and reslizumab. Pilot data with mepolizumab in EGPA patients suggest that its use may allow for reduction of corticosteroid doses, reducing steroid dependence in patients. [30] Controlled trials of mepolizumab are ongoing. [19]
Baldini et al have created a chart reviewing the treatment of EGPA during induction, maintenance, and refractory disease. [24]
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Granuloma with a central core of eosinophilic debris surrounded by a peripheral palisade of epithelioid histiocytes and eosinophils.
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Bilateral papules and nodules with central necrosis.
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Magnified view of papules and nodules with central necrosis.
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Distal digital purpuric papule.
