Symptoms of Cat Scratch Disease
Cat scratch disease typically presents with a papule or pustule developing 3-30 days after a cat scratch or bite, followed by regional lymphadenopathy approximately 3 weeks after inoculation, with lymphadenopathy generally resolving within 1-6 months. 1, 2
Primary Symptoms
- Initial skin lesion (papule, pustule, or rarely vesicle) at the site of inoculation 3-30 days after a scratch or bite 1, 2
- Regional lymphadenopathy occurring approximately 3 weeks after inoculation 1, 2
- Lymph node suppuration in approximately 10% of cases 1, 2
- Lymphadenopathy typically resolves within 1-6 months 1, 2
Systemic Symptoms
Less Common Manifestations
- Extranodal disease develops in ≤2% of cases 1, 2
- Generalized macular, maculopapular, or morbilliform rash (in about 5% of patients) 5
- Parinaud oculoglandular syndrome (unilateral granulomatous follicular conjunctivitis with ipsilateral preauricular and submandibular lymphadenopathy) 1, 6
- Ocular complications including neuroretinitis, multifocal retinitis, uveitis, and retinal artery occlusion 6
Severe Complications (Rare)
- Encephalopathy (almost exclusively in children and young adults) 1, 3
- Hepatosplenic involvement with micro abscesses 4
- Osteomyelitis 7, 4
- Endocarditis 7
Clinical Course
- Most cases are self-limited and resolve spontaneously within 2-4 months 5, 3
- In temperate climates, higher rates are reported in autumn and winter 7
- Approximately 80% of cases occur in children and adolescents 5
- Atypical presentation is seen in up to 25% of cases 7
Diagnostic Considerations
- Serologic testing is the preferred diagnostic method 1, 2
- PCR of lymph node tissue specimens can be used in difficult cases 1, 2
- High titers (>1:256) of immunoglobulin G antibody to B. henselae are diagnostic 3
- Culture of blood, CSF, and/or lymph node specimens has low yield 1
Cat scratch disease should be considered in the differential diagnosis of any patient with regional lymphadenopathy, especially with a history of cat exposure. The characteristic progression from inoculation site lesion to regional lymphadenopathy is the hallmark of this condition 1, 3.