Gotta admit, I never had this kind of problem when I lived in Texas, but once I returned to the midwest, back in full force! Had such PAINFUL cracks in my fingertips, especially thumbs & what finally healed them was googling & getting info to help. www.youtube.com/watch?v=xC_iKN7CXBI
I tried coconut oil, lotions, creams......finally settled on a triple antibiotic ointment along with the covering mentioned in the video. I think keeping them covered was the key. I'm allergic to the gum in bandaids, so I used gauze & paper tape, but THEN kept them covered with finger cots when at work or at other times when they needed the protection, sliding them up my fingers to give them air on a regular basis. Also, ALWAYS used rubber gloves over that & use them constantly now. After a week my two thumbs & two other fingers have felt WONDERFUL. Now I just use rubber gloves when washing dishes & cleaning, plus use a Nivea cream. Once healed, however, I think any oil or lotion would do.
Good luck, everyone, & here's to happy, supple hands!