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Cat Scratch Disease



Related narrative: Groin Mass (Cat Scratch Disease)

The differential diagnosis of lymphadenopathy includes infections such as cat scratch disease, atypical mycobacteria, tularemia, plague, brucellosis, syphilis, lymphogranuloma venerium, sporotrichosis, histoplasmosis, toxoplasmosis, mononucleosis; primary neoplasm (lymphomas); and metastatic neoplasms. The nodal mass can also be mistaken for soft tissue sarcomas.

Cat scratch disease was classically described in 1950, but it was not until 1990 that immunohistochemical and genetic tests established the fastidious gram-negative bacillus Bartonella henselae as the causative agent. Cat scratch disease is the most common human manifestation of infection with this agent. The transmission is usually from the bite or scratch of a cat or kitten. A primary cutaneous papule/pustule develops within 3-10 days and lasts 1-3 weeks. Regional lymphadenopathy, usually upper extremity or neck, develops in 90% of typical cases within 1-7 weeks and is usually the presenting symptom. In half of cases there is a single enlarged node, 20% have multiple nodes at a single site, and 30% present with nodes at multiple sites. In 1/6 of patients there is suppuration associated with the lymphadenopathy.

The presentation is typical in 90% of cases. The other 10% may present with Parinaud's oculoglandular syndrome (50%)(granulomatous conjunctivitis and periauricular lymphadenitis), granulomatous hepatitis or splenitis, atypical pneumonitis, osteitis, endocarditis or encephalopathy (2-4%). Atypical manifestations may result in a delay in diagnosis. Both the typical and atypical syndromes are usually self-limited, resolving in several weeks.

Antimicrobial therapy is usually not necessary in normal hosts. Clinically effective antibiotics include rifampin, ciprofloxacin, gentamycin, trimethoprim and sulfamethoxazole, clarithromycin and azithromycin. When suppuration is present, aspiration or incision and drainage may be necessary for patient comfort.


Mandell: Principles and Practice of Infectious Diseases, 5th ed., Copyright 2000 Churchill Livingstone, Inc, 2447-2450.

Conrad DA, Treatment of cat scratch disease, Curr Opin Pediatr - 01-Feb-2001; 13(1): 56-9.

This page was last modified on 26-Sep-2002.