Cat Scratch Disease (CSD) is caused by Bartonella henselae, a Gram-negative intracellular bacterium. It is typically transmitted through scratches, bites, or flea exposure from cats.
Clinical Features:
- Primary Lesion:
- Small papule or pustule at the site of inoculation (3–10 days after exposure).
- Regional Lymphadenopathy:
- Tender, swollen lymph nodes (axillary, cervical, or epitrochlear depending on the scratch site).
- Suppuration can occur in 10–30% of cases.
- Systemic Symptoms (In Some Cases):
- Fever, malaise, fatigue.
- Rarely, hepatosplenic involvement, neuroretinitis, or encephalopathy.
Diagnosis:
- Clinical diagnosis based on history of cat exposure and lymphadenopathy.
- Serology (IgG, IgM for Bartonella henselae) or PCR if uncertain.
- Biopsy (rarely needed) may show granulomas with central necrosis.
Treatment
- Mild cases: Usually self-limiting, resolves in weeks.
- Moderate-severe cases: Azithromycin (5 days) speeds resolution of lymphadenopathy.
- Disseminated disease: Doxycycline + Rifampin for 4–6 weeks