Cat scratch disease in humans is typically a benign, subacute regional disease of the lymph nodes (lymphadenopathy) resulting from dermal inoculation of the causative agent. This agent has been demonstrated to be Bartonella (formerly Rochalimaea) henselae, a bacterium that has been isolated from immunocompromised patients with bacillary angiomatosis, a distinctive and potentially deadly vascular proliferative host response in skin, bone, or other organs associated with the presence of clumps of bacteria.