Tinea Types: Common Dermatophyte Infections Case 6 Negative-Culture Tinea Corporis

February 1, 2004
Robert P. Blereau, MD
Robert P. Blereau, MD

A 49-year-old man was concerned about a right flexor forearmlesion that had been increasing in size for 6 weeks.The light pink, well-demarcated, 5-cm, circular lesion featuredslight peripheral elevation with ulceration, crusting,and a relatively clear central area. A culture of materialfrom the lesion was negative for fungi. A potassium hydroxideevaluation was not performed.

A 49-year-old man was concerned about a right flexor forearmlesion that had been increasing in size for 6 weeks.The light pink, well-demarcated, 5-cm, circular lesion featuredslight peripheral elevation with ulceration, crusting,and a relatively clear central area. A culture of materialfrom the lesion was negative for fungi. A potassium hydroxideevaluation was not performed.The eruption cleared completely after a 4-weekcourse of econazole cream applied twice daily. The negativefungal culture result may have occurred because thespecimen was taken from an area of the lesion that containedrelatively little crusting.Since the infection spreads centrifugally, specimensfor fungal testing must be taken from the periphery oradvancing edge of the lesion, where dermatophytes arepresent.