Oregon Esthetician State Board

What signifies hypopigmentation when seen under a Wood's lamp?

1. Yellow or orange

2. Yellow green or blue white

3. Light violet or purple

4. Brown

The correct answer is: Yellow green or blue white

When observed under a Wood's lamp, hypopigmentation is characterized by a yellow-green or blue-white fluorescence. This occurs because the lack of melanin in the skin does not absorb UV light in the same way as normal or hyperpigmented areas do. The presence of a yellow-green or blue-white hue indicates the absence or low presence of melanocytes, which are the cells responsible for producing melanin, the pigment that gives skin its color. This distinctive fluorescence helps estheticians and dermatologists to assess skin disorders more accurately, particularly when examining conditions like vitiligo or post-inflammatory hypopigmentation, where the skin appears lighter than the surrounding tissue. By recognizing this pattern under the Wood's lamp, professionals can appropriately identify and treat various skin issues effectively.