Wood's Light

Excerpt

American physicist Robert Wood developed what is now known as the Wood's light or Wood's lamp. Wood's lamp is a source of long wave ultraviolet light and can be used to detect the fluorescence in skin and hair, which is a feature of some dermatophytes. It has diagnostic utility in the detection of inconspicuous scalp lesions. Apart from its use in the diagnosis, the Wood's lamp can be used to select infected skin and hairs for laboratory investigation. It also can detect disorders of skin pigment, including vitiligo and other skin irregularities. The lamp can also be used to determine if the patient has a corneal abrasion on the surface of the eye.

Normally, the light will appear purple or violet, and the skin will not fluoresce. However, certain bacteria, fungi, or changes in pigmentation of patient skin will cause the affected area of the skin to change color under light; hence this is used for inspection and detection of certain fungal infections. Wood's light is not a therapeutic or treatment device.

The room needs to be completely dark before the use of Wood's light to create the dermal illumination. This test is performable by any healthcare worker, but to properly interpret the findings, it is best if a dermatologist or other experienced provider administers the test.