Cat-scratch disease

Background

• Caused by Bartonella henselae

Clinical Features

A lesion on the hand of a person with cat-scratch disease.

Enlarged lymph node in axilla with cat scratch on hand.

• History of cat (normally kitten) exposure
• Most commonly present about 2 weeks after exposure
• Lymphadenitis proximal to exposure

Parinaud's oculoglandular syndrome

• Due to direct inoculation of the eye
• Causes conjunctivitis, ocular granuloma, periauricular adenopathy

Differential Diagnosis

Lymphadenitis

Infectious

• Reactive adenitis
• Bacterial lymphadenitis
• Tuberculous lymphadenitis
• Cellulitis
• Cat-scratch disease
• Parotitis
  • Suppurative parotitis
  • Viral parotitis
• Lymphangitis
• Toxoplasmosis
• Tularemia
• Viral disease
  • HIV-AIDS
  • Cytomegalovirus
  • Epstein-Barr Virus
• Fungal disease
• Reactive adenitis

Non-Infectious

• Malignancy
  • Lymphoma
  • Metastatic cancer
• Rheumatologic Disease
  • Kawasaki Disease
  • Systemic lupus erythematosus
  • Sarcoidosis
  • Juvenile Idiopathic Arthritis
  • Langerhans Cell Histiocytosis
• Cutaneous Lesions:
  • Bacillary angiomatosis
  • Purpura
  • Hematomas
  • Angiomas
  • Dermatofibromas
  • Nevi
• Drug reaction
  • Phenytoin or Carbamazepine
• Postvaccination
• Sarcoidosis
• Salivary gland diagnoses

Evaluation

Work-up

• Indirect fluorescence assay (IFA) or ELISA testing

Diagnosis

• Generally clinical diagnosis

Management

• Immunocompetent
  • Adult (>45kg): Azithromycin 500mg PO x1, then 250mg/day x 4 days
  • Child (<45kg): Azithromycin 10mg/kg x1, then 5mg/kg per day x 4 days

Disposition

• Admit if immunocompromised or evidence of systemic disease.
• Otherwise discharge with PCP follow-up.

See Also

• Bartonella henselae
• Mammalian bites