MS-3196

A 67-years-old man with a history of gout and seasonal allergies visits his primary care physician. He reports experiencing a burning sensation on the left side of his chest for the past three days, which has been disrupting his sleep. He has also had a fever for the last three days.

During the examination, the physician observes erythema and occasional vesicles on the left side of the patient’s chest. The affected area extends from above his nipple to under his axilla.

What is the most probable diagnosis?