Same issue here. Rash (really bad--red spots, like yeast but I don't think it was yeast because I did multiple yeast strips and bleach runs, that eventually became bleeding sores) in cloth, no rash in disposables (like, the rash would be gone within a few hours of putting her in sposies). I almost gave up on cloth because of it. I tried so many things--tons of different wash routines and detergents, multiple strips--I even switched from prefolds and Mother-Ease Airflow covers to fleece pockets (Kawaii) in the hopes that the fleece would keep her dry and get rid of the rash. Nothing helped except disposables and Desitin.
After a few weeks, though, a fairly mild rash started coming back when she was in disposables. That made me go back to cloth since if she had a rash in either, I figured she might as well be in cloth (the environment is my main reason for wanting her in cloth). What we do now is put her in Kawaiis (or sometimes cotton fitteds without covers) during the day and a disposable diaper at night.
I'm still not totally sure what the issue is, though. When I put her back in cloth I cut out a lot of things I'd been doing, sort of a cloth elimination diet, to see if I could pinpoint the issue. The things I stopped using were:
- flushable liners
- coconut oil on her bottom
- any other creams or lotions on her bottom
- cloth wipes (we use disposable Kirkland brand wipes from Costco now)
- laundry additives (I'd tried vinegar, Grapeseed extract, and a few other things at various times)
- an older type of Kawaii diapers that had a funny feeling fleece (maybe it was microsuede or something?) in them
- cloth diapers at night
I've since sloooowly added things back into our routine, one at a time, checking for reactions. So far the flushable liners are back in use without a problem, as are the older Kawaiis. Next up I'll try adding the cloth wipes back in.
I did change our wash routine, too. Previously I'd tried Country Save, Tide, and a homemade detergent made from Borax and washing soda. Now all I use is a big squirt of blue Dawn, and a scoop of Oxyclean. That's it. It seems to work very well. I have a portable apartment top loading washing machine and it has no trouble with the Dawn. I do a full wash cycle on cold with nothing in it but the diapers, and the a heavy duty hot cycle (two wash cycles, one rinse) with the Dawn and Oxyclean. She stays pretty much rash-free now. Once in a while she gets an immediate bad reaction to a poop; if that happens, we put her in a disposable with Desitin and it's gone by the next diaper change.
The frustrating thing (for a perfectionist like me) is that I still don't know what the source of our issues were. Was it the detergents? Was it the cloth wipes, for some reason (the disposable ones seem much softer and gentler to me)? Was it the cloth-friendly diaper creams I used (Baby Bottom Better, coconut oil)? I do think she might be allergic to coconut oil, since it seems like she gets red when I put it on her face. Was it being in cloth all night for 13+ hours at a go, and being in a disposable at night is the golden ticket? Is it that she was teething and so her poop was really acidic for a long time, and she needed the Desitin barrier that we could use when she was in disposables? I'm still not sure.
All that to say that if you really want to stick with cloth, you could try doing what I did:
1) Put her in disposables and slather on the Desitin.
2) Wash all your cloth diapers with a splash of bleach, in hot water. Then wash them a couple of times with a squirt of blue Dawn and a scoop of Oxyclean to remove any possible detergent residue. Rinse several times. Machine dry.
3) Leave her in disposables until her rash completely clears up, plus another week or two after that.
4) Put her back in disposables. Don't use any liners or creams. Use very simple fragrance-free disposable wipes (the Costco ones are great). Put her in a disposable at night (we actually do two disposables, one on top of the other, for nighttime!) See if she stays rash-free (or mostly rash-free) for a few weeks. If so, add back other things you might want (like liners or cloth wipes), one at a time, very slowly. If she gets a rash, cut out the thing you just added back and see if she stays rash-free.
No guarantees, because she might have totally different issues than my DD, but that's what we've been doing! Keep us posted--believe me, I KNOW how frustrating this can be and I don't even want to think of the hundreds of hours I've spent thinking and working on and researching this issue! My DH wanted me to give up just so I'd quit angsting about it.