What is the treatment for a cat scratch?

Treatment for Cat Scratch

For cat scratches, immediate wound washing is essential, followed by azithromycin treatment if cat scratch disease develops with lymphadenopathy (500 mg on day 1, then 250 mg for 4 days for adults; 10 mg/kg then 5 mg/kg for children <45 kg). 1

Initial Management of Cat Scratches

1. Immediate wound care:

   • Wash the wound promptly with soap and water 1
   • Clean thoroughly to remove potential pathogens
   • Apply an antiseptic solution if available

2. Wound assessment:

   • Evaluate depth and location of scratch
   • Check for signs of immediate infection (redness, swelling)
   • Document when the injury occurred and the circumstances

3. Tetanus prophylaxis:

   • Administer tetanus toxoid booster if:

     • 5 years since last dose for dirty wounds

     • 10 years for clean wounds

   • Tdap preferred over Td if not previously given 1

Cat Scratch Disease Management

If symptoms of cat scratch disease develop (typically 3-30 days after scratch):

Clinical Presentation

• Papule or pustule at scratch site
• Regional lymphadenopathy (occurs ~3 weeks after inoculation)
• Lymph nodes may remain enlarged for 1-6 months
• Suppuration occurs in ~10% of cases
• Extranodal disease (CNS, liver, spleen, bone, lung) in ≤2% of cases 1

Treatment Algorithm

1. For typical, uncomplicated cat scratch disease:

   • First-line therapy: Azithromycin 1
     • Adults >45 kg: 500 mg on day 1, then 250 mg daily for 4 days
     • Children <45 kg: 10 mg/kg on day 1, then 5 mg/kg daily for 4 days

2. For severe or disseminated disease:

   • Consider longer courses or alternative antibiotics:
     • Rifampin, ciprofloxacin, trimethoprim-sulfamethoxazole 2
     • In severe cases with hepatosplenic involvement, gentamicin may be effective 3

3. For immunocompromised patients with bacillary angiomatosis:

   • Erythromycin 500 mg four times daily or doxycycline 100 mg twice daily for 2 weeks to 2 months 1

Special Considerations

Immunocompromised Patients

• Higher risk for developing severe disease from Bartonella infection 1
• May develop bacillary angiomatosis or peliosis hepatis
• Require more aggressive treatment and monitoring 4

Pregnant Women

• If long-term suppression of Bartonella infection is required, erythromycin should be used
• Tetracyclines should be avoided during pregnancy 1

Prevention

• HIV-infected persons should consider risks of cat ownership 1
• Avoid rough play with cats and situations likely to cause scratches
• Adopt cats >1 year old in good health
• Implement flea control for cats 1

Treatment Efficacy

The evidence supporting antibiotic treatment for cat scratch disease is moderate. In a placebo-controlled study, azithromycin was associated with more rapid reduction in lymph node size compared to placebo 1. However, many cases of cat scratch disease in immunocompetent hosts are self-limiting and may resolve without antibiotic therapy 2, 5.

Common Pitfalls

1. Delayed diagnosis: Cat scratch disease should be considered in patients with unexplained lymphadenopathy and cat exposure
2. Inadequate wound cleaning: Immediate thorough cleaning is critical to prevent infection
3. Overtreatment: Uncomplicated cases in immunocompetent hosts may not require antibiotics
4. Undertreatment: Immunocompromised patients require more aggressive therapy and monitoring
5. Missing disseminated disease: Watch for signs of systemic involvement, especially in immunocompromised patients