[Observation of tinea unguium by neutral red staining]

To evaluate the viability of dermatophytes in tinea unguium, we applied neutral red staining (NRS) for nail powder obtained from direct microscopic examination (DME) of positive tinea unguium patients. The nail powder from tinea unguium patients by grinder was applied following three sets of examinations, NRS, DME, and culture on Mycosel medium. The positive rates of nail powder obtained from 50 tinea unguium patients were 35 (70%), 37 (74%) and 2 (4%), respectively. Correlation of three sets of examinations were as follows: twenty-five patients were NRS positive, DME positive and culture negative, 10 patients were NRS negative, DME positive and culture negative, and 8 patients were NRS positive, DME negative and culture negative. These findings suggest that application of NRS for nail powder from tinea unguium patients is a practical method for evaluation of the viability of fungal elements.