Wood's lamp examination for the diagnosis of tinea infection has decreased to near disuse because of the gradually declining number of dermatophytes that fluoresce under ultraviolet light.2,5 Exceptions include tinea capitis caused by zoophilic Microsporum canis and Microsporum audouinii, which fluoresce blue-green; tinea (pityriasis) versicolor caused by Malassezia furfur, which fluoresces pale yellow to white; and erythrasma caused by Corynebacterium minutissimum, which fluoresces bright coral red. Candida infection and tinea cruris do not fluoresce.