I think one thing is to keep his diaper area clean and dry, then moisturize/block with cream. So after you wipe him when changing him, fan his bottom a little or otherwise let him air out for a while so that the wet wipe fluid dries off, then apply diaper cream (or your prescribed cream) before putting him in his fresh diaper. We were prescribed hydrocortisone cream for eczema and it helped a ton, though we try to use that sparingly because it's a steroid.Anyone dealing/dealt with baby eczema? Poor guy has been so itchy lately even with moisturizer and prescribed cream. It might have been made worse by a bout of diarrhea he's had this past week, either from a virus or teething. Really want to give him some relief, and worry he might get a scratch or eczema lesion infected with staph or something.
Another thing you could do is get hypoallergenic diapers. Those seemed to help my kid through the worst parts, and then we were able to switch back to normal diapers after. I dunno if that was a placebo effect or anything, but it seemed to help us.