What is the treatment for eosinophilic pneumonitis?

Treatment of Eosinophilic Pneumonitis

Corticosteroids are the cornerstone of treatment for eosinophilic pneumonitis, with systemic prednisone at 1-2 mg/kg for severe cases requiring hospitalization or presenting with weight loss, followed by a prolonged taper to prevent relapse. 1

Acute vs. Chronic Eosinophilic Pneumonia: Treatment Approach

Acute Eosinophilic Pneumonia

• Initiate systemic corticosteroids immediately upon diagnosis, as delayed treatment can lead to fatal respiratory failure 2, 3
• Acute eosinophilic pneumonia presents with sudden febrile illness and life-threatening respiratory failure, requiring urgent intervention 3
• Treatment with corticosteroids results in rapid reversal of respiratory failure and complete recovery, generally without relapse 3
• The diagnosis is confirmed by bronchoalveolar lavage showing >25% eosinophils, distinguishing it from infectious pneumonia 4

Chronic Eosinophilic Pneumonia

• Start prednisone at 1-2 mg/kg daily for severe presentations (small-caliber esophagus, significant weight loss, or hospitalization required) 1
• For less severe cases, lower initial doses may be appropriate, but the response should be prompt and dramatic 2
• Plan for prolonged therapy: 58% of patients relapse when steroids are discontinued or tapered too quickly 5
• The majority of patients (75-83%) require long-term low-dose oral corticosteroid maintenance therapy to prevent relapse 5

Maintenance and Relapse Prevention

Long-term management is critical, as relapses are common and occur in the majority of patients:

• Maintain low-dose corticosteroids indefinitely in patients who relapse during tapering attempts 5
• When attempting steroid withdrawal, taper very slowly over months while monitoring for clinical, hematologic, and radiologic signs of relapse 5
• Relapses respond promptly to reinstitution of corticosteroid therapy 5
• Only 17% of patients successfully discontinue steroids without relapse 5

Treatments NOT Recommended

Avoid the following therapies, as they have no demonstrated benefit in eosinophilic pneumonitis:

• Cromolyn sodium: No apparent therapeutic benefit 1
• Leukotriene receptor antagonists: May provide symptomatic relief at high doses but have no effect on eosinophilia 1
• Anti-TNF therapies: No benefit demonstrated 1
• Immunosuppressive agents (azathioprine, 6-mercaptopurine): Insufficient evidence for use 1

Emerging Therapies for Refractory Disease

• Benralizumab (anti-IL-5 receptor antibody) has shown significant efficacy in hypereosinophilic disorders, with 74% of patients achieving sustained response at 48 weeks 1
• Mepolizumab and other IL-5 targeted therapies are increasingly used in eosinophilic lung diseases, particularly for steroid-refractory or relapsing cases 4, 6
• These biologics should be considered when patients cannot tolerate long-term corticosteroids or have frequent relapses despite maintenance therapy 4

Critical Diagnostic Considerations

Before initiating treatment, meticulously investigate potential causes:

• Medications and toxic drug exposures (most common reversible cause) 4
• Parasitic infections (especially in patients with travel history) 2, 4
• Inhaled substances including tobacco smoke 3
• Systemic diseases, particularly eosinophilic granulomatosis with polyangiitis if extrathoracic manifestations are present 4

Prognosis

The long-term prognosis is excellent with appropriate treatment:

• All patients in long-term follow-up studies (mean 10.2 years) remained well with proper management 5
• Complete recovery is expected with timely corticosteroid initiation 2, 3
• The primary challenge is managing relapses, not achieving initial remission 5