Michigan Esthetician State Board Practice Exam

How will a thick corneum layer appear under a Wood's Lamp?

1. Bright red

2. White fluorescence

3. Black light

4. Blue hue

The correct answer is: White fluorescence

The appearance of a thick corneum layer under a Wood's Lamp is characterized by a white fluorescence. This phenomenon occurs because the thicker stratum corneum (the outermost layer of the skin) can trap certain products and debris, which fluoresce when exposed to ultraviolet light. In this context, the presence of conditions such as dryness, scaling, or certain types of skin disorders can also contribute to the bright white appearance when illuminated by the Wood's Lamp. Other visual effects observed under a Wood's Lamp—like bright red, black light, or blue hues—are associated with different skin conditions or features. For instance, bright red might indicate inflammation or infection rather than a thick stratum corneum, while black light does not fluoresce or have specific skin diagnostic uses in this context. A blue hue could be indicative of other specific conditions or bacterial presence but is not representative of a thick corneum layer either. Thus, the distinctive white fluorescence from the thickened skin layer is an important identifier when performing skin analysis with a Wood's Lamp.