Hello, My Fiance Is Having The Worst Issue With His

Hello, my fiance is having the worst issue with his feet. For starters his symptoms include dry itchy feet, blistering and cracking- sometimes open cuts due to the previous. They are often inflammed and we use over the counter cortisone cream. It hardly helps, mind you he's a working man. He speads at least 8hrs in heavy not very breathable boots. He's from Nebraska and came to Washington state 4 years ago. He explains this issue has been on and off since his arrival, I'm lead to assume it must me a climate adjustment. What is this condition and what should I do to ease the irritation????