Re: Alkaline Lakes and Cracked Skin
I have not had this problem but my rudimentary background in chemistry tells me that if I had this problem I would buy a small bottle of shampoo having a fairly high Ph. When leaving the water for the day or for a break I would apply a small amount to the hands paying special attention to areas where I have the most trouble and then rinse them after a few minutes. I'm sure you get the idea behind this suggestion. Many products have the Ph listed on the container or you can stop into a salon and ask someone for a acidic rinse or shampoo.
You could also try your hand (no pun intended) at compounding and create your own high Ph lotion by adding a tad of vinegar to a pre compounded product but you may get some undesirable results such as the compound separating due to the influx of an acidic solution. First choice would be the beauty products, second would be mixing small batches on my own to see what will hold together and create a non greasy hand balm. Since you have found that the medicated cream you are using relives the dry cracking skin in a few days you have a source of treatment, what I am suggesting is a mitigation treatment.
That's the best I can do but if this were my problem I would give them a go.