A 46-Year-Old Man Comes to the Physician's Office for a Pruritic

A 46-year-old man comes to the physician's office for a pruritic rash.  The patient was in his usual state of health until 2 months ago, when dark red lesions appeared over his wrists.  The lesions progressed, and a few weeks later he developed similar lesions on his lower legs.  This morning, the patient saw some "white lines" in his mouth and called for an urgent appointment.  He has no fevers, chills, weight loss, or diarrhea.  The patient has a history of hypertension, which is controlled with lisinopril.  He does not use tobacco or alcohol, but has a remote history of intravenous drug use.  Physical examination shows multiple, discrete violaceous papules and plaques over the flexural surfaces of the patient's wrists and lower legs as shown in the image below.  Examination of the buccal mucosa shows whitish lacy streaks with a slight background erythema.  The rest of his physical examination is unremarkable. The diagnosis is confirmed with the appropriate studies.  Which of the following is the most appropriate next step in evaluation of this patient?

A) Anti-hepatitis A antibodies
B) Anti-hepatitis B surface antibodies
C) Anti-hepatitis C antibodies
D) Cytomegalovirus-specific antibodies
E) Epstein-Barr virus-specific antibodies