Psoriasiform Dermatitis: A Peculiar Presentation in the Setting of Staphylococcus aureus Bacteremia and Hepatitis C

Psoriasis is a multifactorial, immune-mediated dermatitis and chronic papulosquamous disease with considerable geographic and ethnic variation. Psoriasiform dermatitis encompasses a wide spectrum of inflammatory conditions, with several major forms represented by psoriasis. This case report presents an unusual case of psoriasis in a patient with <i>Staphylococcus aureus</i> bacteremia and untreated hepatitis C. A 64-year-old female with untreated chronic active hepatitis C presented with a one-and-a-half-month history of a spreading, pruritic, and painful erythematous rash, initially on her feet and extending to her inner thighs. Examination showed skin breakdown from scratching. Methicillin-sensitive <i>Staphylococcus aureus</i> (MSSA) bacteremia was identified, and nafcillin was started. Initial differential diagnoses included cryoglobulinemia, leukocytoclastic vasculitis, and allergic drug reaction. Serological tests showed decreased C4 (17) and total complement (31), elevated erythrocyte sedimentation rate (ESR) (100), and negative cryoglobulin and antinuclear antibody (ANA). A skin biopsy confirmed psoriasis. Topical betamethasone was prescribed, leading to marked improvement in the rash and skin lesions after two weeks. A stepwise, logical approach is essential in cases of rapidly spreading erythematous rashes. A detailed medication, social, and past medical history is crucial. Diagnostic evaluation should include a laboratory/serological workup (to rule out leukocytoclastic vasculitis and cryoglobulinemia) followed by a skin biopsy for confirmation of the diagnosis.