Derm Dx: Bluish-grey skin discoloration

A 39-year-old Hispanic male with a long history of systemic lupus erythematosus presents complaining of bluish-grey discoloration on his forearms and shins. The patient is not sure how long he has had this problem.

His lupus is currently well controlled but requires multiple medications including prednisone, hydroxychloroquine and mycophenolate mofetil. He also takes calcium, vitamin D and alendronate.