A 35-year-old male with known hepatitis C infection presents with joint pain and a rash on his legs. Laboratory tests show mild renal impairment and microscopic hematuria. What could be the potential causes and next steps?
This patient may be experiencing a type of vasculitis known as cryoglobulinemia, which is associated with hepatitis C. Cryoglobulinemia can lead to joint pain, rash (typically purpura), and kidney involvement. Further investigation should include tests for cryoglobulins, rheumatoid factor, and complement levels. A skin or kidney biopsy might be needed for definitive diagnosis.