What should you know about wood light pityriasis versicolor?

Pityriasis versicolor, also called tinea versicolor, is a superficial yeast-related skin condition. It often creates lighter, darker, or subtly pink patches with fine scaling, commonly on the chest, back, shoulders, or neck. Under ultraviolet light, affected areas may show a change in contrast or a faint yellowish or coppery fluorescence. The appearance is not always present, and normal skin products, sweat, or other rashes can alter what is seen. A positive-looking glow does not identify every cause of discoloured skin, while a quiet examination does not exclude the condition.

A clinician usually combines the lamp examination with the shape and distribution of the patches, surface scale, symptoms, and sometimes a skin scraping viewed under a microscope. The colour can remain uneven after the yeast has been treated, so improvement in infection and return of the skin's usual colour may happen at different speeds.

Arrange a dermatology assessment if patches are spreading, recurring, or difficult to distinguish from other causes of [Dark Patches On Skin](/symptoms/dark-patches-on-skin/) or [White Patches On Skin](/symptoms/white-patches-on-skin/). Treatment may involve [Topical Antifungal Treatment](/treatments/medical-dermatology/topical-antifungal-therapy/), [Medicated Shampoo Treatment](/treatments/medical-dermatology/medicated-shampoo-therapy/), or, for selected widespread or persistent cases, [Oral Antifungal Treatment](/treatments/medical-dermatology/oral-antifungal-therapy/). Use the medicine exactly as prescribed and avoid sharing towels, clothing, or applicators. A [Skin Rash](/symptoms/skin-rash/) or [Scaly Skin](/symptoms/skin-scaling/) page may help you compare symptoms, but it cannot replace an examination.

Seek prompt medical advice when the skin is painful, rapidly changing, blistered, oozing, very inflamed, or associated with fever. Book an appointment when the diagnosis is uncertain, the face or a large area is involved, symptoms return repeatedly, or treatment causes marked irritation. A Wood's lamp is an assessment tool rather than a treatment, and a clinician may choose a different test if the appearance does not fit pityriasis versicolor.

Ask whether the pattern fits [Tinea Versicolor](/conditions/tinea-versicolor/), whether a scraping is useful, which treatment suits the affected area, and how to tell persistent colour change from ongoing infection.