A 32-year-old male presented with a 24-hour history of rash. He reported tingling and mild pain radiating to his right arm that started 2 days earlier. On physical examination, he had normal vital signs. There was a vesicular rash on deep blue base on his right shoulder (Figure 1). No other abnormal findings were noted. A complete blood count and biochemistry were within normal limits. The patient denied any previous or current use of medications, traveling abroad, or history of any disease.
What is the diagnosis?
Lesions on blue skin base.