Ivory/milky-white fluorescence on Wood's Lamp Examination is seen in ______:

Ans. B. Vitiligo* Ivory/milky-white fluorescences on Wood's Lamp Examination is seen in Vitiligo* The loss of pigment from the skin is the hallmark of vitiligo which can usually be easily seen by the naked eye in dark- skinned people.* It may, however, be very difficult to appreciate in fair skinned people because the difference in color of normal and abnormal skin is hardly any.* The normal function of melanin is to block and absorb the light.* Since there is less or no epidermal melanin in the vitiligo-affected patches, it cannot block the light emitted from deeper layers of the skin.* The vitiligo-affected skin appears like window of blue white/ivory white light with sharp margins.* Wood's lamp is hence helpful in the diagnosis of vitiligo, especially in the fair-skinned people.Wood's Lamp ExaminationWood's lamp examination is a diagnostic test wherein the skin or hair is examined while exposed to the black light emitted by wood lamp. Black light is invisible to the naked eye because it is in the ultraviolet spectrum, with wavelength just shorter than the colour violet. The lamp glows violet in a dark environment, because it also emits some light in the violet part of the electromagnetic spectrum.A traditional wood lamp is a low-output mercury arc covered by a Wood filter (Barium silicate and 9% Nickel oxide) and emits light at wavelength 320-450nm (peak 365nm).Various diseases and their colour on Wood's Lamp examinationDiseaseColour on Wood's LightTinea capitis* Microsporum species blue-green (M cam's, M audouinii, M ferrugineum, M distortum);* Trichophyton schoenleini dull blue.* MST Trichophyton species with the exception of T. schoenleinii, are non-fluorescentErythrasmaCoral PinkPityriasis versicolorFaint yellowPseudomonasGreenScabiesFluorescein solution fills the burrows and fluoresces on Wood's light.PorphyriaUrine, feces, blister fluid fluoresce red or pinkVitiligoIvory or milky white