One of the methods through which doctors can confirm the vitiligo diagnosis is by using the Woods Lamp (black light).
This equipment emits ultraviolet light on a wavelength of 365 nanometers, making a vitiligo patient's skin glow yellow green or blue. In contrast, the healhy skin will have no reaction to the UV light.
It is used to detect several skin conditions including fungal and bacterial infections and skin coloring changes such as vitiligo.
The Woods Lamp test must be conducted in a dark room and the skin area being examined must not be contaminated with any agents (eg. topical medication, soap, deodorant or makeup). This means washing your hands just before the exam might yield a false positive result.
The health care provider will take several precautions such as advising you not to look directly in the ultraviolet light or providing you protective goggles when examining the face.
The Woods Lamp examination holds no risk and you won't feel anything during the procedure.
The Woods Lamp emits ultraviolet light on a wavelength of 365 nanometers and was invented by Robert Williams Wood in 1903. Initially, black light was produced with a special glass and was used in communications.
This test reveal different colors according to the type of skin disease, which may include:
- Golden Yellow (Tinea Versicolor)
- Pale Green (Trichophyton Schoenleini)
- Bright Yellowgreen (Microsporum Audouini or M. Canis)
- Aquagreen To Blue (Pseudomonas Aeruginosa)
- Pink To Pinkorange (Porphyria Cutanea Tarda)
- Ash-Leaf-Shaped Spot (Tuberous Sclerosis)
- Bluewhite (Leprosy)
- Pale White (Hypopigmentation)
- Purplebrown (Hyperpigmentation)
- Yellow green or blue (Depigmentation, Vitiligo)
- Bright White (Albinism)