(BMJ)—A 22-yo man w/ HIV presented w/ black crusted lesions on his face that began as red pustules and papules, w/ intermittent fever, 40 days earlier. Lesions progressed despite tx w/ acyclovir for suspected varicella. Exam: facial lesions w/ thick, dark, raised lamellar crust. Lab test confirmed dx. What is it?
Histoplasmosis
Secondary syphilis
Kaposi sarcoma
Keratotic scabies
Cutaneous lymphoma
You are correct. Treponema pallidum particle agglutination assays and rapid plasma reagin titer were positive, confirming secondary syphilis. HIV serology was also positive. Rupioid syphilis (malignant syphilis) is a rare, explosive, widespread form of secondary syphilis characterized by papulopustular eruptions that rapidly transform into ulceration w/ thick, dark, raised, lamellated, adherent crusts. Co-infection w/ HIV is usually reported, suggesting that immunocompromise is a risk factor.

BMJ 2019;367:l5932