From the Guidelines
Cat scratch disease should be treated with azithromycin 500mg on day 1, followed by 250mg daily for 4 additional days for patients weighing ≥45.5 kg, as it has been shown to reduce lymph node size by 80% at 30 days 1. The disease is caused by Bartonella henselae and typically presents as a papule or pustule at the scratch site, followed by regional lymph node swelling. Some key points to consider in the management of cat scratch disease include:
- The disease course varies, but lymphadenopathy generally resolves within 1–6 months 1
- Extranodal disease develops in ≤2% of cases, and bacillary angiomatosis can occur in immunocompromised patients 1
- Diagnosis may be difficult due to the fastidious nature of the organism, but serological testing and PCR can support the diagnosis 1
- A positive Warthin-Starry silver stain of infected lymph node tissue is useful to confirm the diagnosis, although it cannot differentiate species of Bartonella 1
- Prevention involves proper cat handling, thorough handwashing after cat contact, and keeping cats free of fleas which can transmit the bacteria between cats. In severe cases or in immunocompromised patients, longer antibiotic courses may be necessary to prevent serious complications such as bacillary angiomatosis or peliosis hepatis. It is essential to note that while usually benign in immunocompetent individuals, the infection can cause serious complications in immunocompromised patients, highlighting the importance of prompt diagnosis and treatment 1.
From the FDA Drug Label
Doxycycline is indicated for the treatment of the following infections: ... Bartonellosis caused by Bartonella bacilliformis. The FDA drug label does not answer the question about cat scratch disease, but Bartonellosis is related to it, as cat scratch disease is caused by Bartonella henselae.
- Key points:
- The drug label mentions Bartonellosis caused by Bartonella bacilliformis, but not cat scratch disease.
- Cat scratch disease is caused by Bartonella henselae, which is not mentioned in the drug label.
- Therefore, no conclusion can be drawn about the use of doxycycline for cat scratch disease based on the provided drug label [2] [3].
From the Research
Causes and Transmission of Cat Scratch Disease
- Cat scratch disease (CSD) is caused by the bacteria Bartonella henselae, a gram-negative bacteria most often transmitted to humans through a bite or scratch from an infected cat or kitten 4, 5, 6, 7.
- The bacteria are transmitted among cats via the cat flea, which plays a role in amplifying the reservoir 4.
- Arthropod vectors, such as fleas or ticks, may also transmit the disease to humans, although this is less common 6.
Symptoms and Diagnosis of Cat Scratch Disease
- CSD typically presents as tender lymphadenopathy, and may also include symptoms such as fever, malaise, and regional lymphadenopathy 4, 5, 6, 8.
- Atypical forms of infection can include Parinaud oculoglandular syndrome, stellate neuroretinitis, persistent fever without localizing signs, hepatosplenic infection, encephalopathy, osteomyelitis, and endocarditis 4, 5.
- Diagnosis is often made through a combination of clinical presentation, history of exposure to cats, and serologic testing, such as indirect fluorescent antibody assays or PCR 4, 6, 8.
Treatment and Management of Cat Scratch Disease
- Most cases of CSD are self-limited and do not require antibiotic treatment 4, 5, 6.
- However, in cases with severe symptoms or complications, antibiotic treatment may be necessary, with options including azithromycin, rifampicin, ciprofloxacin, trimethoprim-sulfamethoxazole, and gentamicin 4, 5, 8.
- Azithromycin has been shown to speed recovery in some cases, although more research is needed to confirm its effectiveness 6.