An 11-year-old girl presented to her general practitioner with painful skin lesions on her arms and legs. Patient history She had a 3-week history of an upper respiratory illness and had been started on amoxicillin for presumed lower respiratory tract infection. Three days after starting treatment, she re-attended with a rash on her arms and legs; her parents were worried that it was caused by a drug allergy.

Apart from a low-grade fever (38°C), she was well and her observations and examination were otherwise unremarkable. What is the diagnosis? Source: thebmj *This case is from Docplexus editorial team for educative purpose only