Repeated toenail trauma
Here the dermatoscopic view depicts subungual haemorrhage. Usually this is secondary to a solitary episode of injury and the blood pigment slowly grows out.
However, in this case the pigment was not really clearing at the nail base because the nail was being repeatedly traumatised by footwear and bleeding was occurring where the nail plate was separating from the nail bed.
In this dermatoscopic view the rounded globules of blood are evident. This picture is very different to the varying widths and colours of the pigmented lines seen in a subungual