Skin Lesions of Bacillary Angiomatosis in a Male

Description

Violaceous papules and deeper dermal nodules are distributed across the anterior chest, shoulders, and proximal upper arms of an adult male, with scattered erythematous macules between more raised vascular lesions. Several nodules appear subcutaneous, creating a dome-shaped contour beneath intact epidermis rather than a purely superficial vesicular eruption. The truncal predominance and bilateral, relatively symmetric spread help frame the process as hematogenous or multifocal rather than confined to a single dermatome. Color and elevation are the story here. Bacillary angiomatosis reflects Bartonella-driven endothelial proliferation, most often Bartonella henselae or Bartonella quintana, and the cutaneous pattern is a classic clue in patients with advanced HIV/AIDS or other forms of immunosuppression. Clinically it can be mistaken for Kaposi sarcoma, cherry angiomas, or pyogenic granuloma, yet bacillary angiomatosis tends to present as friable red-to-violaceous papules and nodules that may enlarge rapidly and bleed with minor trauma; systemic involvement (hepatic peliosis, bone pain from osseous lesions, fever) shifts management urgency. Biopsy typically shows lobular capillary proliferation with epithelioid endothelial cells and a neutrophil-rich inflammatory background, and Warthin-Starry or silver staining can demonstrate bacilli, guiding antibiotic therapy (often doxycycline or erythromycin) rather than oncologic treatment. Use this image to teach recognition of HIV-associated dermatologic infections in infectious disease and dermatopathology courses, or to support differential diagnosis figures contrasting bacillary angiomatosis with Kaposi sarcoma in clinical manuals and patient-safety guidelines for immunocompromised care settings. It also fits case reports on Bartonella infection, vascular tumor mimics, and treatment-response documentation in outpatient HIV clinics. Anatomical accuracy verified by SciePro's Medical Advisory Board.