A 32-year-old man came to a doctor with complaints of painless rashes that appeared on his knees 4 months ago and now start to appear on his elbows too. The rashes itch and bleed when scratched. The patient notes that on his elbows rash appeared after he had been scratched by a house cat. Physical examination detects dense erythematous plaques 2 to 3 cm in diameter on the knees and elbows. The plaques have a clear contour and are covered in silvery scales. What is the most likely diagnosis in this case?