Step 2

Dermatology 2

A 16-year-old boy comes to the office complaining of itchiness and rash on his upper back for the past week. He says his girlfriend first noticed the rash on his nape seven days ago, which then spread to cover most of his upper back and shoulders. Two weeks ago, he went on a trip with his family to Indonesia and stayed in a beach resort for four days. Past medical history is unremarkable, and he does not take any medications. His pulse is 75/min, respirations are 18/min, blood pressure is 110/75 mm Hg, and his temperature is 37.0°C (98.6°F). Body mass index (BMI) is 25.9 kg/m2. Physical examination shows well-demarcated, hypopigmented macules over the back, chest, and shoulder girdle.

Which of the following is the most appropriate test to confirm the diagnosis?

  • A) Lesion scrapings with potassium hydroxide (KOH)
  • B) Patch testing
  • C) Skin biopsy
  • D) Skin culture
  • E) Wood’s light examination


Danielle Uayan


Dr. Ted O'Connell