With the utility of nail dermoscopy to supplement the diagnosis of onychomycosis, studies have been done in describing common findings. However, most of these were based in Europe and the Americas. Given the geographical variation of onychomycosis, a local study is needed.

The general objective of this cross-sectional study is to determine the different patterns among the clinical subtypes of laboratory diagnosed onychomycosis patients seen at the Philippine General Hospital (PGH).

Clinically suspected Filipino onychomycosis patients seen at the PGH - Department of Dermatology, and at the PGH inpatient wards were recruited. All patients underwent the following: direct KOH microscopy, fungal culture studies, and nail clipping with PAS staining.

A total of 75 samples were included; 93.33% of the samples were categorized as DLSO subtype, 5.33% as TDO, and 1.33% as PSO. The three most common onychoscopic patterns were subungual hyperkeratosis (93.33%), chromonychia (85.33%), and longitudinal striae in 81.33%. KOH was positive in 57.33% of the cases, cultures in 38.67% and PAS stain in 80%. Onychoscopic pattern was not associated with clinical type of onychomycosis and causative organism. Negative KOH result was associated with linear edges (p=0.02).

Among patients with clinical and laboratory diagnosed onychomycosis, linear edges and jagged proximal edges were associated with negative KOH microscopy and fungal CS, respectively. Hence, in situations where such examinations are negative despite a strong clinical suspicion of onychomycosis, the above onychoscopic findings can be used for empirical diagnosis.