Which finding on Wood’s lamp examination is characteristic of tinea capitis?

• A. Hair fluoresces yellow-green
• B. Hair fluoresces blue
• C. Hair fluoresces red
• D. No fluorescence

Answer: (A)

Wood's lamp helps visualize fungal elements by causing certain species to fluoresce under ultraviolet light. In tinea capitis caused by Microsporum species, infected hair shafts commonly glow bright yellow-green under the Wood's lamp. This fluorescence pattern is a classic clue pointing toward Microsporum as the cause, distinguishing it from organisms like Trichophyton species, which often do not fluoresce or show little fluorescence. So, the yellow-green glow of the hair is the finding most consistent with tinea capitis due to Microsporum. Keep in mind that Wood's lamp is a useful adjunct and not definitive—confirmation with culture or microscopy is still standard.