Suggest Remedy For Fluid Blisters In Hand

I have RA and several food allergies. For the past 3 months I have been experiencing amall fluid filled blisters on my hands. They are along the sides of my fingers and are now spreading across the top of my hand. I have seen my RA, my family docotr and a doctor at a walk-in clinic. None of them have any idea as to what could be causing it. I have tried a topical cortisone cream and oral over-the-counter aleergy medicine, neither have had any affect. Do you have any idea what could be causing this?