Case Presentation: The patient is a 54-year-old male, with history of HIV (diagnosed in 2004), previous history of treated syphilis, inflammatory bowel disease (IBD) and hypertension. He presented with non-pruritic rash that spread from the face to the trunk and extremities except the palms and soles. The rash started as circular macules then became nodular and ulcerated with subsequent crusting. Some of the lesions were foul smelling and painful. Furthermore his dog used to licks the lesions. He has not been lately compliant with the antiretroviral regimen (bictegravir/emtricitabine/tenofovir). He complained of fever and chills prior to admission. He had also fatigue throughout. He spiked fever on admission 39.4°C, otherwise the rest of the vitals were stable. The physical exam revealed skin rash without lymphadenopathy. There were well-demarcated firm pink papules and plaques with thin layer of overlying scale on the face. The rest of the skin exam raveled pink papules and plaques with central necrosis and scales (Image 1,2). The palms and soles were spared. Laboratory work-up showed white blood cell count of 7 x10(3)/L, hemoglobin of 9.1 g/dL, platelets of 335 x10(3)/L, sedimentation rate was 91 mm/h, creatinine of 1.27 mg/dL, and normal liver enzymes. He was started on vancomycin and ampicillin-sulbactam empirically to treat superimposed infection. Cultures from the open painful lesions had methicillin-sensitive staphylococcus aureus (MSSA), he was treated accordingly with doxycycline. The skin lesions eventually improved . Other work -up was negative including gonorrhea from multiple sites, lyme serology, thyroid function test, respiratory pathogen panel, rocky-mountain spotted fever serology, tick borne-illness, histoplasma urinary antigen, and serum cryptococcus antigen. IgG was positive for HSV and VZV. HIV viral load was 35 copies/mL. Treponema palladium antibodies were positive, and RPR titers were elevated 1:32 (was previously 1:1 five years ago). The skin biopsy showed mixed inflammatory infiltrates in keeping with secondary syphilis. The diagnosis of lues maligna (LM) was confirmed; the patient was treated for secondary syphilis with intramuscular penicillin benzathine G, 2.4 million units.

Discussion: Syphilis can pose a diagnostic challenge because the skin lesions could take different forms. The skin lesions in our patient were nodular, ulcerated and crusted, raising concern of fungal or mycobacterial infection. The ulcerated areas raised suspicion of pyoderma gangernosum since he had IBD. Herpetic infection was on the differential. The high titers of RPR and the skin biopsy confirmed the diagnosis of syphilis. The patient was diagnosed with LM, which is a rare form of secondary syphilis. LM usually occurs in severely malnourished, alcoholic and HIV-infected patients. Serological and histopathological methods help establish the diagnosis, however high clinical suspicion is the key in the diagnosis.

Conclusions: Lues Maligna is a rare manifestation of a common disease. Physicians should be vigilant of this diagnosis especially among HIV patients.

IMAGE 1: Image1: Noduloulcerated lesions on the back

IMAGE 2: image 2:Noduloulcerated lesions on the leg