What Is Wood's Lamp Used For?

The lamp can make differences in pigment, scale and some organisms stand out more clearly than they do in ordinary room light. A clinician may use it when assessing lighter or darker patches, some fungal infections, pigment loss or changes in hair shafts. The colour seen under the lamp is a clue, not a diagnosis by itself.

The examination is usually performed in a darkened room with the lamp held near the skin without touching it. Cosmetics, creams, clothing fibres and surface debris can affect what is seen, so the area may need to be clean before assessment.

Follow the clinic's instructions and tell the examiner about creams, makeup, self-tanner or treatments on the area. Avoid applying a new product immediately before the visit unless instructed. During the examination, keep still and report discomfort, although the light itself should not be felt as heat.

A clinician may combine the observation with a skin scraping, swab, dermoscopy or another test. Bring a list of products and medicines if the patch has been treated already, since they can change its appearance.

Arrange an assessment for a new, spreading or unexplained colour change, persistent itch, scaling, pain or hair loss. Seek prompt care for a rapidly changing mole, bleeding lesion, ulcer or severe inflammation; a Wood's lamp cannot rule out every important skin condition.

Ask what the lamp findings suggest, whether another test is needed, and whether you should stop any cream before testing. Request clear instructions on treatment while the diagnosis is being confirmed.