Bacillary angiomatosis is an opportunistic ailment of immunocompromised persons displaying as vascular proliferations caused by Bartonella Henselae and Bartonella Quintana gram-negative bacilli.
What is Bacillary Angiomatosis?

Bacillary Angiomatosis. (A) Multiple erythematous nodules on the face. (B) Close-up view of multiple exophytic nodules. (C) Clumps of tangled, dark bacilli on a Warthin–Starry stain (×100). Bacillary angiomatosis. Mejía F, Seas C - The American journal of tropical medicine and hygiene (2014). Not altered. CC.