How is eosinophilia managed?

Management of Eosinophilia

The management of eosinophilia requires identifying and treating the underlying cause, with helminth infections being the most common identifiable etiology in travelers and migrants, followed by organ-specific eosinophilic diseases like eosinophilic esophagitis, and finally consideration of clonal or idiopathic hypereosinophilic syndromes. 1, 2

Initial Diagnostic Approach

Define the Clinical Context

• Obtain detailed travel and migration history to assess risk for parasitic infections, as helminths cause 19-80% of identifiable eosinophilia in returning travelers and migrants 1, 2
• Assess for gastrointestinal symptoms (dysphagia, food impaction, abdominal pain) which suggest eosinophilic esophagitis or parasitic infection 1, 2
• Evaluate for respiratory symptoms (cough, wheezing, dyspnea) which may indicate pulmonary eosinophilic syndromes 3
• Screen for atopic conditions (allergic rhinitis, atopic dermatitis, asthma) as 50-80% of patients with eosinophilic conditions have allergic diatheses 2

Severity Stratification

• Mild eosinophilia: 0.5-1.5 × 10⁹/L 1
• Moderate eosinophilia: 1.5-5.0 × 10⁹/L 4
• Severe eosinophilia: >5.0 × 10⁹/L, requiring urgent evaluation for end-organ damage 4, 5

Parasitic Infection Workup (First Priority)

Diagnostic Testing

• Perform concentrated stool microscopy and/or fecal PCR for all patients with travel history to endemic regions 1, 6
• Obtain serology for specific helminths based on geographic exposure (schistosomiasis, strongyloidiasis, filariasis) 1, 2

Empiric Treatment for Travelers/Migrants

For asymptomatic eosinophilia in returning travelers with endemic exposure, empiric treatment is recommended: 2, 6

• Albendazole 400 mg single dose PLUS ivermectin 200 μg/kg single dose 2, 6
• This combination covers most common helminths including hookworm, ascariasis, and strongyloidiasis 6

Pathogen-Specific Treatment

• Strongyloidiasis: Ivermectin 200 μg/kg daily for 2 days 6
• Schistosomiasis: Praziquantel 40 mg/kg in two divided doses for 1 day 6
• Hookworm/Ascariasis: Albendazole 400 mg single dose 1, 6
• Trichuriasis: Albendazole 400 mg daily for 3 days 1

Critical pitfall: Strongyloidiasis can cause hyperinfection syndrome in immunocompromised patients; always treat empirically before starting immunosuppression in at-risk individuals 1

Eosinophilic Esophagitis Management (Second Priority)

When to Suspect

• Dysphagia, food impaction, or upper GI symptoms with eosinophilia warrant endoscopic evaluation 1, 2
• Peripheral eosinophilia occurs in only 10-50% of adults and 20-100% of children with eosinophilic esophagitis, so normal blood counts don't exclude the diagnosis 2

Diagnostic Confirmation

• Perform upper endoscopy with at least 6 biopsies from 2 different esophageal sites 1, 6
• Diagnosis requires >15 eosinophils per 0.3 mm² (high-power field) in esophageal tissue 1, 2

Treatment Options

First-line therapy options (choose one): 1, 6

1. Proton pump inhibitors (PPIs): Twice daily dosing for 8-12 weeks 1, 6

   • Achieves histologic response in approximately 42% of patients 1
   • Even if symptoms improve, endoscopic follow-up is necessary as symptoms correlate poorly with histologic activity 1

2. Topical corticosteroids: Moderate certainty evidence for reducing esophageal eosinophils to <15/hpf 1

   • Decreases blood eosinophil counts in 88% of patients 2
   • Candida infection may occur in a small proportion; treat with topical antifungals while continuing steroids 1

3. Dietary elimination: Two-food elimination diet (milk +/- wheat or egg) for 8-12 weeks with dietitian support 2, 6

   • Allergy testing is NOT recommended for choosing dietary restrictions 2

Monitoring and Follow-up

• Repeat endoscopy with biopsy after treatment initiation to assess histologic response, as symptoms do not reliably predict disease activity 1, 6
• Histologic remission: <15 eosinophils per 0.3 mm² 1, 2
• Deep remission: <5 eosinophils per 0.3 mm² 2
• Medical treatment with topical steroids reduces stricture development, so long-term anti-inflammatory therapy is important even in asymptomatic patients 1

Critical pitfall: Untreated esophageal eosinophilia progresses to fibrostenotic disease over time, with >80% developing strictures if diagnostic delay exceeds 20 years 1

Hypereosinophilic Syndrome Evaluation (Third Priority)

When to Consider

• Persistent eosinophilia >1.5 × 10⁹/L after excluding parasites and organ-specific diseases 4, 7
• Presence of end-organ damage (cardiac, neurologic, pulmonary, dermatologic) 5, 7

Essential Testing

• Assess for clonal myeloid disorders: Test for FIP1L1-PDGFRA, PDGFRB, and FGFR1 rearrangements 5, 7
• Flow cytometry and molecular studies for aberrant T cells (lymphocyte-variant HES) 5
• Cardiac evaluation with echocardiography and troponin to assess for eosinophilic myocarditis 5

Treatment Based on Etiology

• Clonal myeloid disorders with PDGFRA/PDGFRB fusions: Imatinib (tyrosine kinase inhibitor) 5
• Idiopathic or lymphocyte-variant HES: Corticosteroids as first-line treatment 5
• Steroid-refractory disease: Hydroxyurea or interferon-α 5
• Mepolizumab (anti-IL-5 monoclonal antibody) is effective as steroid-sparing agent but availability varies 5

Special Populations and Considerations

Patients with Concomitant Atopic Disease

• Joint management by gastroenterologist and allergist is recommended for refractory cases with significant atopic disease 1, 2
• Optimize treatment of allergic conditions concurrently 2

Severe Eosinophilia with Organ Damage

• Urgent evaluation and treatment required when eosinophils >5.0 × 10⁹/L with cardiac, neurologic, or pulmonary involvement 4, 5
• Corticosteroids should be initiated promptly for life-threatening complications while completing diagnostic workup 3, 5

Monitoring Treatment Response

• Repeat eosinophil counts after treatment to assess response 2
• For eosinophilic esophagitis, histologic assessment is mandatory as clinical response does not predict tissue healing 1