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Bacillary Angiomatosis — SCE Infectious Diseases MCQ

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ModerateHIV MedicineBacillary AngiomatosisSCE Infectious Diseases

A 45-year-old man with advanced HIV (CD4 15) develops a widespread papulopustular rash with negative blood cultures. Skin biopsy shows perivascular neutrophilic infiltrate with clumps of bacilli on Warthin-Starry silver stain. He has a cat at home. What is the diagnosis?

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Correct answer: E — Bacillary angiomatosis (Bartonella henselae or B. quintana)

Perivascular neutrophilic infiltrate with clumps of bacilli on Warthin-Starry stain and cat exposure in advanced HIV is diagnostic of bacillary angiomatosis (BA), caused by Bartonella henselae (cat contact) or B. quintana (homelessness/body lice). BA presents as vascular papulonodular skin lesions that can mimic KS. Treatment is Doxycycline 100 mg BD (or Erythromycin 500 mg QDS) for at least 3 months. BA can also cause peliosis hepatis (blood-filled hepatic cystic spaces). ART initiation is essential for immune reconstitution.

Reference: BHIVA 2022 – OI guidelines; NICE CKS 2024 – Bartonella