[Diagnosis of cutaneous fungal infection]

The Japanese Dermatological Association produced some guidelines for the management of cutaneous fungal infection in cooperation with the Japanese Society for Medical Mycology, in which the importance of an accurate diagnosis of the fungal infection before antifungal treatment is emphasized. Here I comment on conventional mycological tests including direct microscopic examination and fungal cultures, which have been listed in the guidelines. Sampling of the clinical specimen is the most important step in mycological tests, so dermatologists should be aware of how and where good specimens are obtained. Direct microscopic examination of a KOH (potassium hydroxide) mounted preparation is the most simple and important test for diagnosing superficial fungal infection and dematiaceous fungal infection, which requires that dermatologists be skilled. The fungal culture is important in determining the therapeutic strategy and prophylaxis of the fungal infection, especially in cases of tinea capitis, tinea corporis, and deep mycoses. It is imperative that dermatologists be fully trained and prepared in order to implement these procedures when the occasion demands.