Background: Many diagnoses may be evoked in the presence of purpuric lesions of the lower limbs in HIV-positive patients. We report here on a Staphylococcus aureus abscess around a vascular prosthesis revealed by unilateral purpuric lesions.
Patients and methods: A 43-year-old HIV-positive man was referred to us with febrile purpura of the left lower limb. His past medical history included a crossover iliofemoral arterial bypass. Clinical examination revealed fever and infiltrated purpuric lesions on the left ankle associated with cyanotic left toes. A skin biopsy showed leucocytoclastic vasculitis. A voluminous right iliac abscess was demonstrated by abdominal and pelvic CT scans. S. aureus was isolated from the skin biopsy, two blood cultures and the periprosthetic abscess. The abscess was drained without replacing the prosthesis and antibiotic therapy consisting of oxacillin was given for 6 months, resulting in complete healing.
Discussion: Vascular prosthetic infections are rare events that can occur early or late after surgery. S. aureus is usually the causative infectious agent. Clinical signs are non-specific and include purpuric lesions, which rarely reveal these infections. The organism may generally be isolated from prosthetic materials and blood cultures. CT scan is the recommended test to visualize prosthetic impairment. Treatment comprises prolonged antibiotic therapy adapted in accordance with the bacterial antibiogram, along with surgical debridement and, preferably, prosthetic replacement.
Conclusion: This case report describes a unilateral purpura revealing a periprosthetic abscess. Dermatologists must be aware of this sign as a potential indicator of prosthetic infection.
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