Emission spectrum of Wood’s light ranges from 320 to 400nm.
Diferente das porfirias:
Soret band is 400-410nm (low UVA and high visible - blue)
Can penetrate window glasses
Need physical blocking sunscreens (specially those containing iron oxide)
“Usual” UVA and UVB sunscreens will not block this!!!
Patient examined in dark room
Use: distinguish epidermal from dermal hyperpigmentation
Visible light and ultraviolet rays penetrate the skin and are partially absorbed in the melanin normally present in the epidermis
Darker or lighter color of the skin depends on the radiation reflected by the skin. Most of the UV rays from the Wood’s lamp are absorbed in the epidermis, with only a small portion reaching the dermis
When there is epidermal hyperpigmentation alllight is absorbed by the excess melanin, thereby increasing the contrast with unaffected skin
When hyperpigmentation is dermal, Wood’s light is absorbed in the epidermis, concealing the hyperpigmentation, that is only clearly visible in normal light
Use: distinguish hypochromia from achromia in fair-skinned individuals
Use: show specific fluorescence
Fluorescence localized to the follicles is pathognomonic of progressive macular hypomelanosis and may be related to C. acnes
Microsporum canis fluoresces - verde brilhante
Malassezia (ex. PV) - verde
Eritrasma - coral-red fluorescence devido a produção de porfirinas pela corinebacteria
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