Diffuse Bier spots.

A 34-year-old man presented with a 6-month history of hypopigmented macules that were interspersed with blanching erythematous macules on the trunk, upper extremities, and lower extremities. Bier spots are small, hypopigmented macules that are usually found on the arms and legs of young adults. The intervening skin may seem erythematous but blanches with pressure so that the hypopigmented macules disappear. This is a benign vascular anomaly.