Norwegian scabies hid in advanced AIDS-associated talaromycosis misdiagnosed as atopic dermatitis: a case report

Abstract

Background: Crusted scabies (Norwegian scabies), a rare variant of scabies infestation, typically manifests in immunocompromised hosts or institutionalized patients with characteristic hyperkeratosis and fissured plaques. In AIDS patients with concurrent opportunistic infections like talaromycosis, scabies diagnosis may be obscured by overlapping cutaneous manifestations, potentially delaying appropriate management. This case highlights the diagnostic challenges in differentiating crusted scabies from treatment-refractory dermatitis in advanced HIV patients. Case presentation: A 46-year-old male with advanced AIDS (the absolute CD4 + count is 3 cells/ul) presented to the emergency department with persistent fever and progressive hyperkeratotic lesions. Two months prior, the patient had been misdiagnosed with atopic dermatitis and treated with dupilumab therapy. Subsequently, talaromycosis-associated febrile symptoms and lymphadenopathy had resolved following liposomal amphotericin B and antiretroviral therapy. Dermatological manifestations, however, remained refractory. Upon readmission, physical examination demonstrated coalescing gray-brown hyperkeratotic plaques with fissures and erythematous denuded areas distributed on the trunk, extremities, and thighs. Histopathologic analysis of biopsy identified Sarcoptes scabiei mites embedded in the stratum corneum, with microscopy of skin scrapings confirming motile mites. Treatment included topical sulfur ointment and oral ivermectin. Gradual resolution of crusts occurred over 4 weeks. Conclusions: This case underscores the imperative for comprehensive dermatological evaluation in immunocompromised hosts with atypical cutaneous presentations.