A lesion showing "milk-white" fluorescence under Wood's light examination is indicative of which condition?

A lesion that exhibits "milk-white" fluorescence under Wood's light examination is characteristic of vitiligo. In vitiligo, the affected areas of skin lose their pigment due to the destruction of melanocytes, leading to patches of lighter skin. When these depigmented areas are examined with Wood's light, they typically fluoresce a bright white color, which is a result of the lack of melanin absorption.

In contrast, conditions like tinea versicolor may reflect with varying colors under UV light, primarily due to the presence of the Malassezia fungus interfering with the normal pigmentation of the skin but not presenting the same "milk-white" fluorescence as vitiligo. Tinea corporis, a fungal infection, typically does not exhibit fluorescence under Wood's light; rather, it may appear red or have other features depending on the stage of the infection. Amelanotic melanoma, while it may lack pigmentation and be difficult to diagnose, wouldn’t typically produce the distinct "milk-white" fluorescence seen in vitiligo. Thus, knowing the specific fluorescence patterns under Wood's light allows for the differentiation of vitiligo from these other skin conditions.