Whip-like rash on the trunk

A woman in her 50s presented with a 10 day history of daily high grade spiking fever (39°C), accompanied by arthralgia involving multiple joints, sore throat, and itchy rash on the chest and back. Skin lesions manifested as multiple red-to-brown, linear plaques resembling whip marks (known as flagellate dermatosis), which persisted during the afebrile period (fig 1). The patient was initially treated at another hospital where blood and urine cultures were unremarkable. Fever of unknown origin was considered and broad spectrum antibiotics were commenced five days after the onset of symptoms.