Bacillary angiomatosis. Clinical and histologic features, diagnosis, and treatment.

Bacillary angiomatosis is a relatively new infection affecting primarily patients with human immunodeficiency virus or others with impaired host defenses. It presents most commonly with multiple red skin lesions, but visceral involvement may also occur, including involvement of the liver and spleen. Because of the dermatologic manifestations, bacillary angiomatosis may be mistaken for Kaposi's sarcoma. The diagnosis is made by identification of the characteristic histologic findings or genetic amplification by means of polymerase chain reaction. The causative agent was recently identified as Rochalimaea henselae, although Rochalimaea quintana may also play a role. Therapy with erythromycin or doxycycline is usually effective.