What is the treatment for cat scratch disease?

Treatment for Cat Scratch Disease

Azithromycin is the first-line treatment for cat scratch disease, with a dosing protocol of 500 mg on day 1 followed by 250 mg for 4 additional days for patients >45 kg, or 10 mg/kg on day 1 and 5 mg/kg for 4 more days for patients <45 kg. 1

Treatment Algorithm

First-Line Treatment

• Azithromycin is recommended as the first-line treatment by the American College of Physicians, with evidence showing more rapid reduction in lymph node size compared to placebo 1
• For patients >45 kg: 500 mg on day 1 followed by 250 mg for 4 additional days 2, 1
• For patients <45 kg: 10 mg/kg on day 1 and 5 mg/kg for 4 more days 2, 1

Alternative Treatments

• If azithromycin is contraindicated, the Centers for Disease Control and Prevention recommends:
  • Doxycycline 100 mg twice daily 1
  • Erythromycin 500 mg four times daily 1
• Other antibiotics showing clinical efficacy include rifampin, ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole, and clarithromycin 3

Treatment Indications

Mild to Moderate Disease

• Many cases of cat scratch disease in immunocompetent hosts are self-limited and may not require antibiotic therapy 3, 4
• Consider treatment for:
  • Moderate to severe lymphadenopathy 4
  • Prolonged symptoms 5
  • Systemic symptoms 4

Severe or Complicated Disease

• Treatment is strongly recommended for:
  • Immunocompromised patients 1
  • Extranodal or disseminated disease (occurs in ≤2% of cases) 2, 1
  • Hepatosplenic involvement 6
  • Neurologic manifestations including encephalopathy 5, 4
  • Ocular involvement (e.g., neuroretinitis) 3, 5

Special Populations

Pregnant Women

• Erythromycin is preferred for pregnant women, as tetracyclines are contraindicated during pregnancy 1

Immunocompromised Patients

• More aggressive and prolonged treatment is needed for HIV-infected patients with bacillary angiomatosis 1
• Long-term suppression with erythromycin or doxycycline should be considered for patients with relapse or reinfection 1

Prevention Measures

• Consider risks of cat ownership, particularly for severely immunosuppressed persons 1
• Choose cats >1 year old in good health 1
• Avoid rough play with cats and situations where scratches are likely 1
• Promptly wash any cat-associated wounds 1
• Implement comprehensive flea control for cats 1
• Do not allow cats to lick open wounds 1

Clinical Pearls and Pitfalls

• Cat scratch disease typically presents with a papule or pustule 3-30 days after a cat scratch or bite, followed by regional lymphadenopathy about 3 weeks after inoculation 2, 1
• Lymphadenopathy generally resolves within 1-6 months, with suppuration occurring in approximately 10% of cases 2
• PCR testing or Warthin-Starry silver stain of infected lymph node tissue can confirm diagnosis in difficult cases 2, 1
• Be aware of potential cross-reactivity between B. henselae and B. quintana in serologic testing 2
• Cat scratch disease should be included in the differential diagnosis of fever of unknown origin and any lymphadenopathy syndrome 4