Figure 4: (a) Cartoon illustration of distal subungual onychomycosis. (b) Clinical feature of distal subungual onychomycosis on the left big toenail (patient). (c and d) Polarized dermoscopy of distal subungual onychomycosis of the nail plate showing a jagged proximal border of the onycholytic area (red asterisk), with yellow-spikes (blue arrows) projecting into the proximal nail plate (×40)