A 49-year-old man was concerned about a right flexor forearm
lesion that had been increasing in size for 6 weeks.
The light pink, well-demarcated, 5-cm, circular lesion featured
slight peripheral elevation with ulceration, crusting,
and a relatively clear central area. A culture of material
from the lesion was negative for fungi. A potassium hydroxide
evaluation was not performed.
The eruption cleared completely after a 4-week
course of econazole cream applied twice daily. The negative
fungal culture result may have occurred because the
specimen was taken from an area of the lesion that contained
relatively little crusting.
Since the infection spreads centrifugally, specimens
for fungal testing must be taken from the periphery or
advancing edge of the lesion, where dermatophytes are