Chao is a 33-year-old Chinese man who presents to the emergency department with a 10-day history of a widespread painful rash over his face, trunk and right shoulder.

Two weeks prior to presentation, Chao consulted a GP regarding a four-week history of neck and upper back pain that he believes is a result of prolonged work as an office clerk.

He had already tried various interventions, including traditional Chinese medicine and acupuncture, which were minimally effective. The GP prescribed a trial of celecoxib. 

Three days later, the skin changes developed, progressing from white milia to a blistering and discharging urticarial rash within one day.