What is the treatment for cat scratch disease?

Treatment for Cat Scratch Disease

Azithromycin is the recommended first-line treatment for cat scratch disease, with a dosage of 500 mg on day 1 followed by 250 mg for 4 additional days for patients ≥45.5 kg, and 10 mg/kg on day 1 and 5 mg/kg for 4 more days for patients <45.5 kg. 1

Treatment Algorithm

For Immunocompetent Patients with Typical Presentation:

• First-line therapy: Azithromycin (dosing as above)
  • Proven to reduce lymph node size with 80% regression at 30 days compared to placebo 1
• Alternative options (if azithromycin is contraindicated):
  • Erythromycin
  • Doxycycline
  • Ciprofloxacin
  • Trimethoprim-sulfamethoxazole 2, 3

For Immunocompromised Patients:

• Extended therapy required: Erythromycin 500 mg four times daily or doxycycline 100 mg twice daily for 2 weeks to 2 months 1
• Close monitoring is essential due to risk of developing bacillary angiomatosis 4
• HIV-infected patients with severe immunosuppression are at particularly high risk for severe Bartonella infections 5

For Patients with Lymphangitis and Progressive Edema:

• Broader coverage is recommended due to potential polymicrobial infection including Staphylococcus aureus and Streptococcal species 1
• Clinical reassessment within 24-48 hours to evaluate response to therapy 1

For Diabetic Patients:

• Amoxicillin-clavulanate 875/125 mg orally twice daily for 5-7 days
• Doxycycline 100 mg twice daily for penicillin-allergic patients 1

Special Considerations

Severe or Disseminated Disease:

• Patients with severe infection (high fever, extensive lymphadenopathy) may require hospitalization and IV antibiotics 1
• Atypical presentations (neuroretinitis, encephalopathy, hepatosplenic infection) occur in up to 25% of cases and require more aggressive treatment 3

Ocular Complications:

• Parinaud's oculoglandular syndrome, neuroretinitis, multifocal retinitis, uveitis, and retinal artery occlusion may occur 6
• These complications require antibiotic therapy even though the evidence base is limited 6

Pregnancy:

• If treatment is required during pregnancy, erythromycin should be used
• Tetracyclines should be avoided during pregnancy 5

Important Clinical Pearls

• Most cases of cat scratch disease in immunocompetent hosts are self-limited and may not require antibiotic therapy 4, 7
• Lymphadenopathy may persist for 1-6 months despite appropriate treatment 1
• The diagnosis is typically made through a combination of clinical presentation, history of cat exposure, and serologic testing with high titers (>1:256) of IgG antibody to B. henselae 7

Prevention Strategies

• Immediate thorough washing of cat scratches or bites with soap and water 1
• Implement flea control for cats (fleas are responsible for cat-to-cat transmission) 5, 1
• Avoid rough play with cats and keep cats' nails trimmed 1
• Immunocompromised individuals should consider the risks of cat ownership 5
• When acquiring a cat, choose an animal aged greater than 1 year that is in good health 5

Follow-up appointments should be scheduled in 1-2 weeks to assess resolution of symptoms, with instructions to return sooner if symptoms worsen 1.