What is the treatment for elevated eosinophils?

Treatment for Elevated Eosinophils

The treatment for elevated eosinophils should be directed at the underlying cause, with corticosteroids being the primary therapy for eosinophilic disorders when no specific etiology is identified. 1, 2

Diagnostic Approach Before Treatment

• A systematic evaluation for underlying causes is essential before initiating treatment, with referral to appropriate specialists based on clinical presentation and severity of eosinophilia 1
• Assess for common causes including:
  • Parasitic infections, especially in those with travel history 1, 2
  • Allergic conditions (rhinitis, asthma, atopic dermatitis) 1
  • Gastrointestinal disorders, particularly eosinophilic esophagitis 3, 1
• Diagnostic workup should include:
  • Stool microscopy and serology for parasitic infections 1, 2
  • Endoscopy with multiple biopsies if gastrointestinal symptoms are present 3, 1
  • Referral to hematology for persistent eosinophilia ≥1.5 × 10⁹/L for more than 3 months 2

Treatment Algorithm

For Parasitic Infections

• Albendazole 400 mg as a single dose for most helminth infections 1, 2
• For strongyloidiasis, ivermectin 200 μg/kg daily for 1-2 days 1, 2
• For schistosomiasis, praziquantel 40 mg/kg in two divided doses for 1 day 2
• For returning travelers with asymptomatic eosinophilia, empiric treatment with albendazole 400 mg single dose plus ivermectin 200 μg/kg single dose 1, 2

For Eosinophilic Esophagitis

• Proton pump inhibitor therapy twice daily for 8-12 weeks 2
• Topical steroids for histological and clinical remission 3, 2
• Two-food elimination diet (milk +/- wheat or egg) for 8-12 weeks with dietitian support 2

For Hypereosinophilic Syndrome and Idiopathic Eosinophilia

• Corticosteroids are first-line therapy for hypereosinophilic syndrome 3, 4
• Prednisone is typically initiated at higher doses and then tapered to the lowest effective dose 4
• Alternate-day therapy may be considered to minimize side effects once control is established 4
• For steroid-refractory cases, consider hydroxyurea or interferon-alpha 5, 6, 7
• Mepolizumab (anti-IL-5 antibody) has been FDA-approved for idiopathic hypereosinophilic syndrome 7

For Myeloid/Lymphoid Neoplasms with Eosinophilia

• Identification of rearranged PDGFRA or PDGFRB is critical as these respond excellently to imatinib 5, 6, 7
• For aggressive forms of hypereosinophilic syndrome and chronic eosinophilic leukemia, cytotoxic chemotherapy and hematopoietic stem cell transplantation may be considered 6, 7

Monitoring Response

• Follow-up eosinophil counts should be obtained after treatment to assess response 1, 2
• For eosinophilic esophagitis, histological remission is defined as <15 eosinophils per 0.3 mm² in tissue biopsies 1
• For persistent eosinophilia despite treatment, consider referral to a hematologist for further investigation 2, 8

Important Considerations

• Persistent eosinophilia of any degree can cause significant end-organ damage, particularly affecting the heart, lungs, and central nervous system 2
• For milder forms of eosinophilia (<1.5 × 10⁹/L) without symptoms or signs of organ involvement, a watch-and-wait approach with close follow-up may be appropriate 5, 6, 7
• A multidisciplinary approach involving specialists from hematology, gastroenterology, pulmonology, and infectious disease may be necessary for complex cases 9, 8

Pitfalls and Caveats

• Many people with helminth infection do not have eosinophilia, so testing for eosinophilia alone is not an adequate screening strategy 2
• Peripheral blood eosinophil counts may not always correlate with tissue eosinophilia in conditions like eosinophilic esophagitis 1, 10
• When using corticosteroids, be aware of potential side effects and consider steroid-sparing strategies when long-term treatment is anticipated 4
• Allergy testing to foods is not recommended for choosing dietary restriction therapy for eosinophilic esophagitis 1