Clinical Challenge: Is This Rash Lyme Disease?

A man, aged 64 years, presents for evaluation of an asymptomatic rash that developed on his left medial mid-thigh three days ago. He spends a substantial amount of time outdoors but denies a history of antecedent tick or spider bite or bee sting. He denies fever, malaise, muscle aches, and joint pain. He has a history of eczema and has ...