Coral red colour on wood lamp seen is

WOOD'S LAMP Hand held device used to diagnose various dermatological conditions. It is a mercury vapour long wave,ultraviolet lamp with an inbuilt wood's filter made of barium silicate with 9% nickel oxide. Opaque to all wavelengths except those between 320 nm and 400 nm with a peak at 365 nm. Flourescence occurs when wood's light is absorbed and radiation of longer wavelengths is emitted. Examination done in dark room. Erythrasma- causative organism- corynebacterium minutissimum shows coral red flourescence due to production of coproporphyrin 3. Pseudomonas:Contains pigments pyoverdin or fluorescein giving green flourescence. Tinea:Flourescence seen in tinea capitis is due to pteridine content.Microsporum- bright green flourescence.Trichophyton- dull greenMalassezia-pale yellow. {Reference: IADVL textbook of dermatology, page 109