Discoid lupus erythematosus

Case history

A 30-year-old woman presents to her primary care physician with a rash affecting her face, neck, ears, and scalp. The rash started as flat, well-demarcated, red, scaly lesions on her face, sparing the nasolabial folds, and is now confluent with spread to her neck and ears. In addition, the lesions have expanded leaving a depressed central area of scarring. There are no known precipitating factors. She is normally fit and healthy, with no significant past medical history. She smokes 10 cigarettes per day, does not take any regular medication, and has not recently taken any over-the-counter preparations.