A mother brought her 9-year-old son to the pediatrician when he developed hypopigmented patches of skin on his body near the end of the summer. At first, she thought she just hadn't applied his sunscreen very well, but then the patches seemed to show a very fine scale like dry skin. He only seemed to have them on his cheeks, chest, and upper arms; however, his mother knew he had been wearing shorts or swim trunks all summer and most of his skin had been exposed to the sun. He occasionally complained about the spots itching. He had a history of mild asthma but was otherwise very healthy. Can you diagnose the patient?