What is the treatment for elevated eosinophils due to parasitic infection?

Treatment for Elevated Eosinophils Due to Parasitic Infection

The treatment for elevated eosinophils due to parasitic infection should be targeted to the specific parasite identified, with albendazole and ivermectin being the most commonly used first-line antiparasitic medications for many helminth infections. 1, 2

Diagnostic Approach

Before initiating treatment, proper identification of the causative parasite is essential:

• Detailed clinical history focusing on:

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

• Initial laboratory tests:

  • Complete blood count with differential to confirm eosinophilia
  • Peripheral blood smear
  • Stool examination for ova and parasites
  • Serological tests for specific parasites
  • Organ-specific imaging if target organ involvement is suspected

Treatment Based on Specific Parasites

Common Helminth Infections

1. Strongyloidiasis:

   • Ivermectin 200 μg/kg/day for 1-2 days 2
   • May present with larva currens (itchy, linear, urticarial rash)

2. Hookworm:

   • Albendazole 400 mg daily for 3 days 2

3. Schistosomiasis:

   • Praziquantel 40 mg/kg twice daily for 5 days 1
   • For neuroschistosomiasis: Add dexamethasone 4 mg four times daily, reducing after 7 days, for 2-6 weeks

4. Filariasis:

   • Diethylcarbamazine (requires specialist consultation) 1
   • Warning: Can cause severe reactions in patients with onchocerciasis

5. Toxocariasis:

   • Albendazole plus corticosteroids for eosinophilic meningoencephalitis 1

6. Cutaneous larva migrans:

   • Ivermectin 200 μg/kg as a single dose or
   • Albendazole 400 mg daily for 3 days 1

7. Onchocerciasis:

   • Ivermectin (dosage requires specialist consultation) 1

Monitoring During Treatment

• Monitor blood counts at the beginning of treatment and every 2 weeks while on therapy 3
• Monitor liver enzymes (transaminases) before starting treatment and at least every 2 weeks during treatment 3
• Follow-up eosinophil counts to confirm resolution of eosinophilia

Important Considerations and Precautions

Potential Complications

• Albendazole may cause bone marrow suppression, aplastic anemia, and agranulocytosis 3
• Patients with liver disease and hepatic echinococcosis are at increased risk for bone marrow suppression 3
• Treatment of neurocysticercosis requires concurrent steroid and anticonvulsant therapy to prevent neurological symptoms 3

Special Situations

• For neurological involvement (e.g., eosinophilic meningitis from Angiostrongylus cantonensis):

  • Corticosteroids (prednisolone 60 mg daily for 14 days) are the mainstay of treatment 1
  • Albendazole (15 mg/kg/day for 14 days) may have similar effects
  • Therapeutic lumbar punctures may be necessary

• For acute neuroschistosomiasis (Katayama syndrome with neurological symptoms):

  • Initial treatment with corticosteroids alone to avoid neurological complications 1
  • Add praziquantel later

When to Discontinue Treatment

• If clinically significant decreases in blood cell counts occur 3
• If liver enzymes exceed twice the upper limit of normal 3

Follow-up

• Regular monitoring of blood counts to confirm resolution of eosinophilia
• For persistent eosinophilia, monitoring for end-organ damage is crucial, particularly cardiac complications
• Delayed treatment can lead to irreversible organ damage

Parasitic infections represent the second most common cause of secondary (reactive) eosinophilia worldwide, after allergic disorders 1. Prompt identification and appropriate treatment are essential to prevent complications and improve outcomes.