<prompt> This lesion developed on the chest of a 35-year-old man during treatment for a respiratory tract infection. What is the diagnosis?Acute urticariaDrug-induced pemphigusErythema annulareFixed drug eruption  <response>: Answer D. Fixed drug eruptionFixed drug eruptions such as this one are common, immune-mediated, cutaneous lesions that appear as annular, edematous, reddish-brown macules or plaques. Residual hyperpigmentation is a hallmark. 