Bacillary angiomatosis is caused by B. henselae and B. quintana, while peliosis is caused only by the former species. These diseases occur most often in HIV-infected pts with CD4+ T cell counts of <100/µL.

• Pts with bacillary angiomatosis present with one or more painless skin lesions that may be tan, red, or purple in color. SC masses or nodules, ulcerated plaques, and verrucous growths also occur. Painful osseous lesions, primarily in the long bones, may develop and appear as lytic lesions on radiography.
• Peliosis is an angioproliferative disorder characterized by blood-filled cystic structures that affects primarily the liver but also the spleen and lymph nodes. Hypodense hepatic areas are usually evident on imaging.
• Both diseases are diagnosed on histologic grounds. Blood cultures may be positive.