How would you diagnose a fungus with numerous microconidia and macroconidia
A 4-year-old boy was taken by his mother to the family doctor for evaluation of a 2-month history of a slowly growing "bump" on the back of his head. The boy had no other siblings nor any pets at home. He attended a day care center weekdays while his mother worked. Examination revealed a happy, alert child in no distress. A raised, scaling lesion 3.5 cm in diameter with a few pinpoint pustules was present on the posterior scalp. A KOH preparation of material from the lesion was negative. A fungal culture of material from the lesion was later positive for a fungus with numerous microconidia and macroconidia typical of Microsporum species.
What additional examination might have revealed this infection while the child was in the doctor's office?
B. Serologic test
C. Ultraviolet light
E. DNA probe