Spot Dx — Can you work out the cause of this breakout?

Vicki is a 56-year-old business owner who presents with a two-day history of painless rash affecting the distal third of both legs.

Test your clinical know-how by taking the quiz below. If you select the wrong answer, have another go — you can try as many times as you like!

<p>Vicki is a 56-year-old business owner who presents with a two-day history of painless rash affecting the distal third of both legs.</p><p>Vicki is usually robustly well, with no past history of note.</p><p>She has a strong family history of ischaemic heart disease and is very proactive about lifestyle management. </p><p>She exercises most days and has just returned from a three-day trail walking event, which was hot, challenging but very satisfying.</p><p>She wore a T-shirt and knee-length shorts with ankle socks and sneakers and fastidiously applied sunscreen and insect repellent to exposed areas. She noticed the rash the night she returned home.</p><p>Vicki is otherwise well, with no infective or systemic symptoms or joint pain.</p><p>Examination findings are unremarkable apart from a palpable, petechial and purpuric lower-extremity rash present circumferentially from just above the ankle malleoli and extending proximally for 5cm (pictured). </p><p>Urinalysis is normal.</p>

Dr Kate Kelso is a GP and medical editor at Australian Doctor.