Derm Dx: White streak on the leg

A mother brings her 4-year-old daughter to the dermatology clinic for her first consultation for a white streak on the leg, which was not present at birth. Twelve months prior, the patient developed very fine pink papules in a linear distribution along the leg and thigh, the mother reports. Subsequently, the papules disappeared leaving only a hypopigmented streak.

The patient denies any associated itch or pain, is otherwise health and takes no medications. Her father has type 2 diabetes. All of her siblings are healthy. What’s your diagnosis?

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