If you Google (does Google get a commission every time I say that? Google Google Google!) "yeast and cloth diapers," you will discover that a) it takes a bit more work to get rid of a yeast rash than it would if you were using disposables and b) there are a great many methods to getting rid of it. Because I haven't tried them all, all I can do is tell you what worked for us.
Many people feel like they need to use disposables while treating yeast; we did not have to. However, there is certainly nothing wrong with going that way.
By the time I discovered it was yeast at a well baby pediatrician visit, it'd been there for at least a week while I thought it was regular diaper rash. So when I figured out what it was, I felt like I had to work quickly to get rid of it...it looked painful! Poor kid. And the routine I stumbled upon worked like a charm, and worked very quickly.
We did three things concurrently:
1. Bleach (on the diapers) UPDATE: See note at bottom of post! I will now use grapefruit seed extract or a mixture instead of just bleach.
2. Sun (on her and the diapers)
3. Monistat cream (on her) UPDATE: I switched to using CJ's Spritz Plus (more natural) to start with and only doing Monistat if it persists.
To start, each load of diaper laundry I did, I included 1/4 to 1/2 cup of bleach. I didn't measure exactly so I couldn't tell you the exact amount, but somewhere in that area. I did an extra rinse the first time I did it (on top of the extra rinse I already do, so an extra extra rinse), but I forgot the next time and it seemed like all the bleach was out, we didn't have any performance issues, and she didn't have any reaction, so after that I just did the one regular extra rinse. You may want to do an extra extra rinse just to be sure. We always wash with a "quick wash" on cold with no detergent, then run the "whitest whites" setting which is a hot water cycle (and includes the aforementioned extra rinse) using Dropps detergent. NOTE: I have a front loader with a separate bleach compartment. You should never put bleach directly on diapers. I take no responsibility for any bleach spots or yellowing of diapers! It's always a risk you take with bleach. It didn't happen to me, but that doesn't mean it won't ever happen! UPDATE: See mixture recommendation at the end of this post.
After each load was done, I sunned the diapers. SO IMPORTANT. To explain this, know that yeast likes dark, moist areas (so is it any wonder it likes to take up camp in vaginas and baby butts?) and it *hates* sun. Yeast and sun is like Hitler and ice cream (I assume Hitler hated ice cream, being evil and all). I kept them outside in bright sun, making sure that the inside of the diaper that was against her was facing the sun, for several hours. This wasn't a big deal, since I usually try to dry anything with PUL, elastic, or velcro in the sun anyway - but this time, I included all the inserts and soakers and wipes as well. If it touched her butt, it got sun.
I also made sure that she had naked butt time every day - in the sun whenever possible. I kept most of her body in the shade, and just exposed the area with the yeast rash to the sun (this involved holding her legs like I was wiping her during a diaper change, to expose the goods to the sun the best). I did this at least once a day for five or so minutes at a time (some days more than once). This gave the area a chance to get nice and dry, and again - yeast hates sun and the sun is a natural antifungal and disinfectant, so doing this really kills it at the source. This is much easier with a non-mobile baby than it is with a crawler or walker, but it can be done!
Finally, twice a day, I put Monistat cream on the rash (ok, I'm cheap, so I used the generic version). When I did this, I used a fleece liner to prevent the cream from getting on the diaper and washed the liner separately with our clothes - and sunned the liner when it was washed. You do have to look a bit to make sure you're getting the cream and not the suppository version. UPDATE: I discovered CJ's Spritz Plus, and it's worked wonderfully. I now use that to start with and only go with Monistat if necessary because it's extra stubborn. UPDATE #2: Some babies may have a sensitivity to the CJ's Plus. I'm not sure what in it causes the sensitivity, but because of that I wouldn't recommend using it all the time - only if battling yeast - and watch to make sure that it's not bothering them.
With the combination of these three treatments, the yeast cleared up almost overnight. I continued the laundry routine for a week or so after it was gone, just to be sure that *every* diaper had the bleach/sun treatment. A few weeks after that, I got thrush AGAIN, which meant that she was more likely to get a yeast rash AGAIN. Sure enough, during my vigilent checks, I noticed a couple of the same red spots pop up. I immediately started the bleach/sun/Monistat [CJ's] again and it never got worse than two or three dots and cleared up extremely quickly.
So that's what worked for us. Your experience may vary, but I think all three parts of the treatment are equally important - the sun is one that's often overlooked but does so much. And it's free and natural! I also started taking probiotics and AZO Yeast pills every day to help prevent another occurrence of thrush, which will help prevent another yeast rash on her (though they are linked, you can have one without the other).
(By the way, if you get thrush, these all are also great ways to treat it: put your nursing bras outside in the sun so the inside of the cups get treated, and also to expose your nipples to sun for a little bit each day...if you can do so without getting arrested. And then some Monistat cream on your nipples twice a day as well, being sure to wipe it off before nursing.)
UPDATE #2: This combo of bleach, tea tree oil, and grapefruit seed extract seems to be a winner for a lot of people (I'm sorry, I can't find the original source - if it's yours speak up and I will credit!):
Use 20 drops Tea Tree oil and 20 drops of Grapefruit seed extract and 1/4 cup of bleach in your prewash. Then wash as normal - if you can, turn up your hot water heater to 130 (don't forget to turn it back down!). The bleach kills the yeast the TTO and GFE kills the spores.