A 24-year-old woman presents with an earache of 4 days in duration. She also reports increased urine production, a skin rash, and bone pain on her scalp. Physical examination reveals otitis media, dermatitis, and exophthalmos. An X-ray of the scalp shows calvarial bone defects. A fine-needle aspirate displays numerous eosinophils. Which of the following is the most likely diagnosis?