How To Treat Blisters With Itching On The Toe?

Area effected is one toe only. Began with itchy area at cuticle on big toe. Sm blister followed a few days after itchy onset. Now have blister on side of toe. Not really itchy. I say blisters, but none have popped and present fluid. Has not spread to any other toe or hands for that matter secondary to scratching (have washed hands after scratching...FYI). Considered contact dermatitis, but very odd that only single toe on single foot has presented. Have taken benedryl, applied cortisone, anti-fungal, and anti-bacterial to no improvement at all. This has been going on for approx 1 month. Any suggestions? Also, no swelling, pain or redness associated.