How is eosinophilia managed and treated?

Management and Treatment of Eosinophilia

The management of eosinophilia should be directed at the underlying cause when identifiable, with treatment urgency guided by the presence of end-organ involvement or life-threatening complications. 1

Diagnostic Approach

1. Initial Laboratory Evaluation:

   • Complete blood count with differential
   • Peripheral blood smear
   • Comprehensive metabolic panel with liver function tests
   • Urinalysis with protein-to-creatinine ratio
   • C-reactive protein
   • Serum tryptase
   • Vitamin B12 levels 1

2. Clinical History Focus Areas:

   • Travel to tropical/subtropical areas
   • Exposure to freshwater
   • Consumption of raw foods
   • Walking barefoot
   • Current and recent medications
   • Allergy history 1

3. Further Investigation Warranted If:

   • Eosinophilia persists >3 months
   • Eosinophil count exceeds 1.5 × 10⁹/L
   • Associated symptoms develop
   • Evidence of end-organ damage 1

Treatment Algorithm Based on Etiology

1. Parasitic Infections

• Hookworm: Albendazole 400 mg daily for 3 days
• Schistosomiasis: Praziquantel 40 mg/kg twice a day for 5 days
• Strongyloides: Ivermectin 200 μg/kg/day for 1-2 days
• Filariasis: Diethylcarbamazine (consult specialist)
• Cutaneous larva migrans: Ivermectin (200 μg/kg single dose) or Albendazole (400 mg/day for 3 days) 1

Important: Exclude Loa loa in people who have traveled to endemic regions before treating with ivermectin 1

2. Drug-Induced Eosinophilia

• Immediate withdrawal of the causative medication 1

3. Eosinophilic Esophagitis

• First-line: Topical steroids to reduce development of strictures 2
• For strictures: Endoscopic dilatation (safe with either balloon or bougie dilators) 2
• Best outcomes: Combine therapeutic dilatation with effective anti-inflammatory therapy using topical steroids 2
• Alternative if PPI causes side effects: Consider switching to diet or topical steroid 2

4. Hypereosinophilic Syndrome (HES)

• Idiopathic HES: Corticosteroids as first-line therapy 3
• Lymphocyte-variant HES: Corticosteroids as first-line therapy 3
• Refractory cases: Hydroxyurea or interferon-α 3
• FDA-approved biologic: Mepolizumab (anti-IL-5 monoclonal antibody) for idiopathic HES 3

5. Myeloid Neoplasms with Eosinophilia

• PDGFRA or PDGFRB rearrangements: Imatinib (highly effective) 3
• Other genetic variants: Targeted therapy based on molecular findings 3

Special Considerations

Eosinophilic Myocarditis

• Requires prompt diagnosis and treatment to prevent irreversible cardiac damage
• Treatment directed at underlying cause (parasitic infection, vasculitis, etc.)
• Steroids often used for idiopathic cases 4

Pulmonary Eosinophilia

• Management directed at underlying cause when identifiable
• Urgency of treatment guided by severity of end-organ involvement
• Biologic therapies increasingly used when cause not easily attributable 5

Monitoring and Follow-up

• Regular monitoring of blood counts to confirm resolution 1
• For persistent eosinophilia, regular monitoring for end-organ damage 1
• Follow-up with complete blood counts necessary to confirm resolution in patients with mild and transient eosinophilia 1

Important Pitfalls to Avoid

1. Delayed treatment: Can lead to irreversible organ damage, particularly cardiac complications 1

2. Missing occult parasitic infections: Consider empirical treatment with albendazole 400 mg plus ivermectin 200 μg/kg for asymptomatic eosinophilia in travelers/migrants with negative initial testing 1

3. Candida infection: May occur in patients with eosinophilic esophagitis treated with topical corticosteroids; manage with topical antifungals while continuing topical steroids 2

4. Underestimating strictures: Endoscopists can underestimate the frequency of strictures and narrow lumen esophagus in eosinophilic esophagitis 2

5. Perforation risk: Eosinophilic esophagitis is the most common cause of spontaneous perforation of the esophagus; if perforation occurs with limited extravasation, manage conservatively with multidisciplinary input 2

6. Psychological impact: The psychological impact of dietary therapy should be appreciated and discussed with patients with eosinophilic esophagitis and their carers 2