What is the treatment for toxocariasis?

Treatment of Toxocariasis

The treatment for toxocariasis depends on the clinical presentation, with albendazole being the first-line medication for visceral larva migrans (VLM) at a dose of 400 mg twice daily for 5 days, while ocular toxocariasis requires a combination approach with albendazole and corticosteroids. 1

Clinical Forms and Diagnosis

• Toxocariasis is caused by the roundworms Toxocara canis and T. cati, with humans becoming infected by ingesting embryonated eggs from soil, dirty hands, raw vegetables, or larvae from undercooked giblets 2
• The clinical spectrum includes several presentations:
  • Visceral larva migrans (VLM): Presents with fever, eosinophilia, wheeze, cough, abdominal pain, and hepatosplenomegaly 1
  • Ocular toxocariasis: Presents with visual changes, retinal granuloma, or uveitis; eosinophilia is less common in isolated ocular disease 1
  • Neurotoxocariasis: Can present with myelitis, encephalitis, or meningitis 1
  • Covert toxocariasis: Milder symptoms that may not be immediately recognized as toxocariasis 3
• Diagnosis is primarily through serology, with marked peripheral eosinophilia typically present in visceral forms 1

Treatment Algorithm

1. Visceral Larva Migrans (VLM)

• First-line treatment: Albendazole 400 mg twice daily for 5 days 1
• In cases of severe or persistent disease, treatment may need to be extended or repeated 3, 4
• Monitor for treatment efficacy through:
  • Initial rise in eosinophilia within a week (expected)
  • Subsequent improvement in clinical symptoms
  • Gradual decrease in eosinophilia and serological titers over at least 4 weeks 3

2. Ocular Toxocariasis

• Requires formal ophthalmological examination 1
• Treatment includes:
  • Albendazole 400 mg twice daily for 2 weeks 1
  • Corticosteroids (topical or systemic) 1, 2
  • Surgical intervention may be necessary in some cases 1
• Joint management with ophthalmology is essential 1
• Prednisolone 40-60 mg once daily in severe disease 1

3. Neurotoxocariasis

• Treatment includes:
  • Albendazole for 3-4 weeks 1
  • Corticosteroids may be added, especially in cases with significant inflammation 1
  • Repeat anthelmintic therapy may be required 1
• Specialist consultation is strongly recommended 1

Special Considerations

• Higher doses or longer treatment courses may be needed for severe or recurrent cases 3, 4
• In cases with marked inflammation or edema on imaging, corticosteroids should be added to prevent inflammatory reactions to dying parasites 1
• Liposomal formulations of benzimidazole carbamates may enhance drug efficacy by improving bioavailability, though these are not yet standard of care 5
• For prevention, recommend:
  • Handwashing after soil contact
  • Routine deworming of pets
  • Discouraging geophagia
  • Proper disposal of pet feces 6

Treatment Monitoring

• Monitor eosinophil count before and after treatment 3
• An initial rise in eosinophilia within the first week of treatment may occur before improvement 3
• Clinical improvement should be observed within 4 weeks of treatment initiation 3
• In recurrent or persistent cases, consider prolonged albendazole therapy 4

Pitfalls and Caveats

• A positive serological test does not necessarily correlate with active clinical infection and must be interpreted in the context of clinical findings 6
• Ocular toxocariasis may occur without systemic eosinophilia, making diagnosis challenging 1
• Preventive treatment should be considered even in asymptomatic cases with moderate to high positive serology to reduce the risk of larvae localizing in critical organs like the brain 3
• Corticosteroids must be used with caution if there is potential co-infection with Strongyloides due to risk of hyperinfection 1