MSFinals-0810
A 42-year-old man visits his primary care physician complaining of thick, well-defined, red patches with silvery scales on the extensor surfaces of his elbows and knees. He has been experiencing these skin lesions intermittently for the past 3 years. The lesions tend to improve during the summer months, worsen during times of stress, and reappear at the site of trauma, particularly where he scratches. A skin biopsy specimen reveals epidermal hyperplasia and parakeratosis, with neutrophils present within the epidermis. What is the most probable diagnosis?