New contrast stain for the rapid diagnosis of dermatophytic and candidal dermatomycoses.

Methods. Skin scrapings were taken from outpatients with superficial dermatomycoses and cultured in Sabouraud dextrose agar with cycloheximide. They were then evaluated under a microscope using both the KOH wet mount technique and the new contrast stain. Two investigators read the slides together but were blinded to all other test results. The new contrast stain contains 1% Chicago sky blue 6B and 8% KOH as the clearing agent. Staining was performed as previously described. Slides were scanned at original magnification 10 to locate blue-staining fungal hyphae. Dermatophytes were confirmed at original magnification 40 on the finding of septate filaments. Candidal yeasts were detected as refractile oval budding yeast cells and/or pseudohyphae after lowering the condenser. Candidal slides were returned to the humidifying chamber and read again the following day to detect any change in staining intensity. A 20% KOH solution was used for the KOH wet mount, and microscopic examination was performed in the usual manner.