Library · Procedure
Wood lamp examination
Make it clearer
A Wood lamp examination consists of shining ultraviolet A light, around 365 nanometers, on the skin. It is an aid in evaluating vitiligo and some skin infections.
What you are looking for is color. In vitiligo, the disease in which the skin loses its pigment, the depigmented patches give off a bright blue-white fluorescence that stands out sharply against the rest of the skin. Fluorescence means that the lesion, when it receives that invisible light, gives off light of a visible color.
And each condition gives off its own color. Erythrasma glows coral red, and that color comes from coproporphyrin III, a pigment made by the organism that causes it. In tinea capitis, which is ringworm of the scalp, hairs infected by certain Microsporum species look green to yellow-green under that same light.
In brief
A Wood lamp examination shines ultraviolet A light, around 365 nanometers, on the skin and helps in evaluating vitiligo and some skin infections.
Under that light, the depigmented lesions of vitiligo show a blue-white fluorescence that stands out against the surrounding skin.
Erythrasma fluoresces coral red because of the coproporphyrin III the organism produces, and in tinea capitis hairs infected by certain Microsporum species appear green to yellow-green.
Sources (3)
- National Center for Biotechnology Information, StatPearls PublishingVitiligo, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingErythrasma, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingTinea Capitis, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated