Dark blood spot under toenail, waxes and wains but there for months.  No obvious physical injury.  Nail beginning to look like some fungus infection, not otherwise infected.  69, diabetic in tight control.  Thoughts, probability of bacterial infection starting?
HI, thanks for using Chat Doctor It is possible that there is a bacterial infection there as well but if there have been long term changes, a fungal infection is likely. You should consider showing the nail to your doctor. If it is a fungal infection, oral antifungals would be needed, all fungal nail infections require oral medication. If there is a co-existing bacterial infection, additional medication would be needed, this may be topical or oral depending on the extent of the problem. I hope this helps