In this clinical challenge, we describe the case of a previously healthy 8-year-old girl who presented to a primary care clinic with fever, reduced oral intake and malaise on day 3 of her illness. Clinical examination revealed that she was tachypnoeic and tachycardic. An erythematous rash was found across the bridge of her nose and cheeks, and several painless ulcers were noted in the oral cavity. Blood investigation showed thrombocytopenia, while urinalysis revealed microscopic haematuria and proteinuria. Useful initial diagnostic imaging studies were discussed, including bedside ultrasound in the ambulatory care setting. It is imperative that primary care providers be vigilant when encountering cases like this.