A 62-year-old man presented to our emergency department with cough, shortness of breath, headache, and a diffuse purpuric rash for 1 week. He had a temperature of 37.1 C, heart rate of 103 beats/min, blood pressure of 159/85 mm Hg, and oxygen saturation of 88% on room air. Physical examination was unremarkable except for the diffuse purpuric rash.

He had a prior medical history of diabetes mellitus and SLE with musculoskeletal (bilateral inflammatory hand arthritis) and hematological (mild thrombocytopenia) involvement. He received the diagnosis 3 weeks prior to his admission and was positive for antinuclear antibodies in a homogenous pattern at a titer of greater than 1: 160 and anti–double-stranded DNA at 41 IU/mL. Rheumatoid factor was also positive at 24 IU/mL. Anti-Smith, antiribonucleoprotein, anti-SSA, anti-SSB, anti–cyclic citrullinated peptide, anti–proteinase 3, and antimyeloperoxidase antibodies were negative. He was not started on therapy at that time for unclear reasons.