a 58 year old construction worker who has no primary care doctor comes to the emergency department because of a non-pruritic rash above his ankles (see figure). physical examination reveals bilateral erythematous and swollen ankles that are mildly warm but non-tender to touch. his overlying skin of both legs show mild scaling and thickened skin. there is no puncture site or visible opening in the skin, although he has prominent varicose veins bilaterally (see figure). his temperature is 37c (98.6f). he appears to be in no acute distress.what is the most likely diagnosis?