Q. A 42-year-old man comes to the physician’s office for a skin rash on his hands and feet for the past 10 days. He says that the rash is highly pruritic and he gets new skin lesions along the scratch lines on previously unaffected areas. He doesn’t have any other complaints. His medical history shows that he has been recently diagnosed with primary hypertension and was prescribed beta-blockers 2 weeks ago. His temperature is 98.6°F (37°C), pulse is 80/min, blood pressure is 126/86 mmHg, and respirations are 13/min. Physical examination shows flat-topped, violaceous, sharply demarcated, confluent papules and plaques on ankles, the volar aspect of both wrists, and also along the scratch lines. The lesions have fine white lines in a lacy pattern on their surfaces. Examination of his oral cavity shows erosion on the right buccal mucosa with the same fine white reticulation. Which of the following is the most likely diagnosis?