What is the appropriate management for a patient with significantly elevated eosinophilia (eosinophil count of 1756)?

Management of Significant Eosinophilia (1756 cells/μL)

A patient with an eosinophil count of 1756 cells/μL requires a systematic diagnostic evaluation to identify the underlying cause, followed by targeted treatment based on etiology, as this level of eosinophilia represents moderate hypereosinophilia that can lead to organ damage if left untreated. 1

Initial Diagnostic Approach

Laboratory Evaluation

• Complete blood count with differential to confirm eosinophilia
• Peripheral blood smear to evaluate blood cell morphology
• Comprehensive metabolic panel with liver function tests
• Serum tryptase levels
• Vitamin B12 levels 1

Parasitic Infection Workup

• Concentrated stool microscopy (at least 3 specimens on different days)
• Strongyloides serology (high yield across all regions)
• Stool PCR for parasites (higher sensitivity than microscopy) 1

Gastrointestinal Evaluation

• Upper endoscopy with biopsies (minimum 2-4 from proximal and distal esophagus)
• Histological assessment for:
  • Peak eosinophil count per 0.3 mm²
  • Basal cell hyperplasia
  • Edema (spongiosis)
  • Eosinophil microabscesses
  • Eosinophil layering
  • Eosinophil degranulation
  • Subepithelial sclerosis 2

Treatment Algorithm Based on Etiology

1. If Parasitic Infection Confirmed:

• Strongyloidiasis: ivermectin 200 μg/kg/day for 1-2 days
• Toxocariasis: albendazole 400mg twice daily for 5 days
• Schistosomiasis: praziquantel 40 mg/kg twice daily for 5 days
• Filariasis: diethylcarbamazine (specialist consultation required)
• Hookworm: albendazole 400 mg daily for 3 days 1, 3

2. If Eosinophilic Esophagitis (EoE) Confirmed:

• First-line therapy options:

  • Proton pump inhibitors
  • Topical corticosteroids (strong recommendation, moderate quality evidence)
  • Dietary therapy (elimination diets or elemental formula) 2, 1

• For refractory disease:

  • Consider biologic therapy with dupilumab (shows most promise based on current evidence)
  • Consider endoscopic dilation if fibrostenotic disease present 2, 1

3. If Hypereosinophilic Syndrome Suspected:

• Prednisone as initial treatment of choice for symptomatic patients
• Monitor for potential organ damage, particularly cardiac complications 4, 5

4. If Clonal Eosinophilia Suspected:

• Bone marrow examination with cytogenetics
• Test for PDGFRA, PDGFRB, or FGFR1 rearrangements
• If positive for PDGFRA or PDGFRB rearrangements, initiate imatinib therapy 4, 5

Monitoring and Follow-up

• Regular assessment of both symptoms and eosinophil counts every 1-3 months

• For EoE, histological remission is defined as:

  • Complete remission: peak eosinophil count <5 eosinophils per 0.3 mm²
  • Partial remission: peak eosinophil count between 5-15 eosinophils per 0.3 mm² 2

• For persistent hypereosinophilia:

  • Monitor for end-organ damage every 3-6 months
  • Consider oesophageal physiological testing in patients with ongoing dysphagia despite histological remission 2, 1

Important Considerations

• Candida infection may occur in a small proportion of patients treated with topical corticosteroids; manage with topical antifungals while continuing steroids 2
• Systemic side effects of topical steroids have not been documented during long-term treatment of EoE patients; however, continued monitoring of bone mineral density and adrenal suppression is recommended in children and adolescents 2
• The psychological impact of dietary therapy should be discussed with patients 2
• If PPI therapy causes unwanted side effects (diarrhea, gastrointestinal infections, magnesium deficiency), consider switching to alternative treatments such as diet or topical steroids 2

This management approach prioritizes identifying the underlying cause of eosinophilia while preventing potential organ damage, with treatment tailored to the specific etiology.