J, my husband (PALS) had eczema and extremely dry skin before ALS but during his skin went completely out of control. He had a severe skin reaction from an antibiotic and combined with the eczema his back, arms, face were covered with rashes and his itching was so bad he would bleed from scratching. It literally took us a year to get it under control.
Long story short, with a lot of trial and error, doctor switched some meds that could add to the itching, used only clothes detergent for sensitive skin and no fragrance, tried to minimize sweet accumulation with all cotton clothes, sheepskin on bed and back of any chair, gently washed back and arms with warm water and applied a baby eczema moisturizer 3 X day. Once it calmed down we washed and lotioned 2X day.
The doctor also had us give him Benadryl at the beginning when it was at its worst, for some reason that I don't remember he didn't want us to use cortisone cream. I researched a lot of skin products and on the Ecxema Society's website found that EXEDERM had no known irritants, surprisingly many well known eczema products do! We used only products from this company, their baby shampoo, body wash, and moisturizer from there on out and it stayed under control.
As Karen said, it's always best to see a doctor to make sure what it is, sometimes it's hard to tell what you're dealing with. My PALS also had fungal issues on occasion. Did you have eczema before ALS? I hope you can find relief, Kate