Hey there! I've got the same problem and was diagnosed.. It indeed does happen in the same place every year, and mainly the hands even though I have seen people's eczema spread up to their wrists...
My doctor said that the causes of eczema are still not conclusively set straight. However, yes it does correlate well with winter, dehydration if you're not drinking enough water, using some bad soap or detergent while washing your hands, excessively washing your hands, and believe it or not, anger and stress..
There is no cure at the moment other that steroidal creams.. He prescribed a cream that heals it overnight, but I stopped using it since it was no good..
An alternative, which very well works with me is changing the soap bar.
He presrcribed the soap blue dove bar. Dove is highly moisturized, and has bethnoate which eases our inflammation by the histamines being released making our dry skin crack.
It works beautifully but ever since my diagnosis 4 years ago, I have not used any soap heavily as much as dove
Another cream that is widely used in my region is called CLIPP.. Again, I don't like creams but only use them in extreme cases when, for example I need to write and my knuckles are rigid.
I am a naturalist, and prefer to use home remedies. For example, I have an aloe plant at all times ready for emergency cases. Aloe helps a lot! And the dove bar! Side by side, they go well during winter
I hope these help you
Take care