I have the same problems and I have discovered that it may be stress related.. However that is not scab for sure! Finger scab only attack the areas between the fingers and not on the top. It is called dermatitis, Dyshidrotic Eczema.
First I thought it was from my girlfriends rabbit, but then I moved to another town, and stayed alone, far away from my girlfriend and the rabbit but the eczema came back..
The eczema started for the first time after I had a car accident and lost a alot of work/money, so I had alot of presure for a quite long time..
It still comes back somehow, but now I dont touch or scratch it and then it dissapears by itself.. But if I starting to scratch back, it will just get more aggresive and the fight ends up when my skin is almost gone.. Anyway, just keep your other fingers away when it starts and see if its working..
Ps. There is some oil and herbs you can use.. Dont try the amoniac, it hurts good but doesn't help!