I can only think of one thing to try:
Soak a cotton ball in Colloidal Silver and apply it to the affected area of just one toe with a band-aid to hold it in place. Do this 2 times a day, morning and evening.
Colloidal Silver safely kills all forms of virus, bacteria & fungus without any side effects.
If your condition is related in any way to bacteria, virus or fungus, it will be cured in less than 1 week.
However I still think that you did something 4 years ago that irritated your big toes in some way. Did you try high heeled shoes 4 years ago? Anything else you may have done to your feet at that time?
Let me know if the Colloidal Silver (CS) works for you. If it works on one toe, then do the other toe. CS is available at any health food store or from Amazon.Com. Colloidal Silver recently cured my TERRIBLE case of pneumonia in just a few days by nebulizing it. I recommend the top rated Mesosilver.