How big are the spots? I have eczema that appears to look a bit like ringworm (I thought that's what I had in the beginning). The spots are small, about pea sized maybe, but can spread out and get itchy and dry and flaky if not treated. They randomly appear and disappear. The spots are not always perfectly circular either. A pic would definitely help for comparison. What strength hydrocortisone is he on? DS appears to have inherited my eczema and for him it is not presenting as circular spots but more as the spread out and flaky but it's just like mine. We were prescribed 2.5% hydrocortisone and I didn't think that was working too well and now he's on something else.
Just fyi, my eczema flares up a lot in the summer, not just in winter. Sorry that you are dealing with this.