A 42-year-old male presents to the dermatology clinic with a 6-month history of persistent, scaly skin lesions. He reports that the lesions initially appeared on his elbows and knees, but they have gradually spread to his scalp and lower back. The plaques are itchy and occasionally painful, particularly if he scratches them. The patient denies any recent illness, but mentions that his symptoms seem to worsen during periods of stress and cold weather.