From the Guidelines
Cat scratch fever, or cat scratch disease, should be treated with azithromycin as the first-line treatment, with a recommended dose of 500 mg on day 1, then 250 mg once daily for 4 additional days for patients weighing ≥45.5 kg, and 10 mg/kg orally on day 1, then 5 mg/kg on days 2–5 for those weighing <45.5 kg, as it has shown to reduce lymph node size by 80% at 30 days in a double-blind placebo-controlled study 1.
Treatment Overview
The treatment of cat scratch disease with antimicrobial agents has had variable results, but azithromycin has shown promising outcomes. According to the 2014 update by the Infectious Diseases Society of America, azithromycin is the recommended treatment for cat scratch disease 1.
Diagnosis and Treatment Considerations
Diagnosis of Bartonella infections, the causative agent of cat scratch disease, may be difficult due to the fastidious nature of the organism and cross-reactivity between species. However, serological testing, PCR, and a positive Warthin-Starry silver stain of infected lymph node tissue can support the diagnosis 1.
Patient Considerations
It is essential to consider the patient's weight when determining the azithromycin dosage, as the recommended dose varies for patients weighing ≥45.5 kg and those weighing <45.5 kg 1. Additionally, the disease course and treatment outcomes may differ in immunocompromised patients, who may require prompt antibiotic treatment and possibly longer courses.
Prevention and Management
Prevention of cat scratch disease includes washing hands after handling cats, cleaning wounds promptly, and avoiding rough play with cats, especially kittens. For mild cases in immunocompetent patients, supportive care, including over-the-counter pain relievers and warm compresses on swollen lymph nodes, may be sufficient. However, severe cases or those affecting immunocompromised individuals require prompt antibiotic treatment 1.
From the Research
Treatment Options
- The majority of cases of cat-scratch disease occurring in normal hosts do not require anti-infective therapy for resolution of infection 2.
- Greatest clinical efficacy has been observed following treatment with rifampin, ciprofloxacin, gentamicin, trimethoprim and sulfamethoxazole, clarithromycin, and azithromycin 2.
- Azithromycin therapy was associated with more rapid diminution in size of infected lymph nodes in one placebo-controlled study 2.
- Severe or persistent cases respond well to several antibiotics, including erythromycin and doxycycline 3.
- Antibiotic therapy is reserved for patients with atypical or severe involvement, including encephalopathy and retinitis 3.
Antibiotic Choices
- Azithromycin has been shown in one small study to speed recovery 4.
- If an antibiotic is chosen, azithromycin is a possible option 4.
- Other antibiotics that may be effective include rifampin, ciprofloxacin, gentamicin, trimethoprim and sulfamethoxazole, clarithromycin 2.
Special Considerations
- Immunocompromised individuals with B. hensalae infection may develop bacillary angiomatosis, bacillary peliosis, and relapsing bacteremia with fever syndrome 2.
- In patients with AIDS, cat-scratch disease may present with bacillary angiomatosis 4.
- Ocular manifestations of Bartonella infection, such as follicular conjuntivitis and regional limphadenopathy, neuroretinitis or retinal infiltrates, may require antibiotic therapy 5.