Cat-scratch disease

Cat-scratch disease is a rare infectious disease, caused by the Gram-negative bacteria <i>Bartonella henselae</i>, that is transmitted to humans via a scratch or bite of an infected cat and that has a variable clinical presentation but that usually manifests with an erythematous papule at the site of inoculation followed by chronic regional lymphadenopathy. Clinical course is usually self-limiting but disseminated illness with high fever, hepatosplenomegaly, granulomatous osteolytic lesions, encephalitis, retinitis, and atypical pneumonia can also occur. Cat-scratch disease can atypically present as parinaud oculoglandular syndrome (unilateral conjunctivitis and preauricular lymphadenopathy).