(Bartonella henselae)

The predominant manifestation of cat-scratch disease (CSD) in an immunocompetent person is regional lymphadenopathy. Fever and mild systemic symptoms occur in approximately 30% of patients. A skin papule or pustule often is found at the presumed site of bacterial inoculation and usually precedes development of lymphadenopathy by 1 to 2 weeks. Lymphadenopathy involves nodes that drain the site of inoculation-typically axillary, but cervical, submental, epitrochlear, or inguinal nodes can be affected. The skin overlying affected lymph nodes typically is tender, warm, erythematous, and indurated. In approximately 25% of people with CSD, the affected nodes suppurate spontaneously. Occasionally, infection can produce Parinaud oculoglandular syndrome, in which inoculation of the eyelid conjunctiva results in conjunctivitis and ipsilateral preauricular lymphadenopathy. Less common manifestations of CSD (approximately 25%) include encephalopathy, aseptic meningitis, fever of unknown origin, neuroretinitis, osteolytic lesions, hepatitis, granulomata in the liver and spleen, glomerulonephritis, pneumonia, thrombocytopenic purpura, erythema nodosum, and endocarditis.