What should you know about Malassezia and Wood's lamp?

A Wood's lamp gives off ultraviolet light so certain skin changes can appear more visible in a dim room. A clinician may use it to inspect colour, scale, or fluorescence and to compare nearby skin. Malassezia-related problems do not have one lamp finding that settles the diagnosis. The result must be interpreted alongside the pattern of bumps, itch, location, products used, and response to previous care.

Arrive with clean skin unless the clinic gives different instructions, and mention creams, cosmetics, or medicines used on the area. The examination is brief and does not involve cutting the skin. Follow the clinician's plan rather than treating a fluorescent colour as proof of infection. If the diagnosis remains uncertain, the clinician may use other examination methods or select a treatment trial based on the full picture.

Seek medical review for rapidly spreading redness, significant pain, pus, fever, or a rash involving the eyes. Arrange follow-up when symptoms continue after the recommended plan or repeatedly return. A Wood's lamp finding should not delay assessment of a painful or worsening eruption.

What finding are you looking for with the lamp? What other conditions can look similar? Do I need another test or a review after treatment?