From the Guidelines
Azithromycin is the most effective antibiotic for cat scratch disease (CSD), caused by Bartonella henselae, and should be prescribed at a dose of 500 mg on day 1 followed by 250 mg for 4 additional days for patients weighing >45 kg, and 10 mg/kg on day 1 followed by 5 mg/kg for 4 additional days for patients weighing <45 kg. This recommendation is based on the strongest and most recent evidence from the Infectious Diseases Society of America 1. The use of azithromycin has been shown to result in significant regression of lymph node size in patients with CSD 1.
Key Considerations
- The diagnosis of CSD can be challenging due to the fastidious nature of Bartonella henselae, and serological testing or PCR may be necessary to support the diagnosis 1.
- Not all cat scratches require antibiotics, and only those showing signs of infection such as increasing redness, swelling, warmth, pus, red streaks, or fever should be treated 1.
- For minor scratches, thorough cleaning with soap and water, applying an antiseptic like hydrogen peroxide, and covering with a clean bandage is often sufficient 1.
Treatment Guidelines
- Azithromycin is the recommended antibiotic for CSD, with a dose of 500 mg on day 1 followed by 250 mg for 4 additional days for patients weighing >45 kg 1.
- For patients weighing <45 kg, the recommended dose is 10 mg/kg on day 1 followed by 5 mg/kg for 4 additional days 1.
- Treatment with azithromycin has been shown to result in significant regression of lymph node size in patients with CSD 1.
From the Research
Effective Antibiotics for Cat Scratch Disease
The most effective antibiotics for cat scratch disease (CSD), caused by Bartonella henselae, are:
- Azithromycin: shown to speed recovery in one small study 2 and appeared to be an appropriate option for the treatment of CSD 3
- Trimethoprim/sulfamethoxazole (TMP/SMX): may be considered as an alternative antibiotic when azithromycin cannot be used 3
- Rifampin: observed to have greatest clinical efficacy in treating CSD 4
- Ciprofloxacin: observed to have greatest clinical efficacy in treating CSD 4
- Gentamicin: observed to have greatest clinical efficacy in treating CSD 4
- Clarithromycin: observed to have greatest clinical efficacy in treating CSD 4
- Doxycycline: used in combination with azithromycin to treat a patient with CSD 5 and shown to be effective in treating severe or persistent cases of CSD 6
Treatment Considerations
- Most cases of CSD are self-limited and do not require antibiotic treatment 4, 6, 2
- Antibiotic therapy is reserved for patients with atypical or severe involvement, including encephalopathy and retinitis 6
- Immunocompromised individuals with B. henselae infection may require prompt medical attention due to the potential manifestation of severe symptoms 5