5 yr old and vulvar rash

KRT

I have no idea if anyone else's DD has this issue. 

I'm at a loss with what to do for DD as she gets a vulvar rash occassionally and usually I can put diaper cream on it and it is cleared up by morning.  Last night she complained after going to the bathroom so I looked at it and she was incredibly inflammed and irritated - worst I have seen.  I ended up putting my son's Triple Paste on really thick 2x after bath and before bed and even put a pantiliner in her underwear so it didn't make her underwear a mess during the night. I put a light application of rash ointment on this morning before daycare.

I have repeatedly gone over wiping with her.  She is very tiny (only 31 lbs) and has trouble holding herself up and reaching from behind to wipe so she will push the toilet paper through to the back from the front or dab.  I emphasized she can't wipe back to front and she definitely doesn't do this.  I am concerned that she is not getting the urine wiped away enough and that the urine is causing the irritation.  I also have to really push fluids with her as she doesn't drink a lot and her urine can get pretty concentrated.  I make sure she is washed well every night at bath time with a mild/sensitive soap.

I am at a loss on what else I can do.  She got really upset last night when I said, "DD, you really have to make sure you are wiping well."  She took this as she did something wrong (she can be sensitive at times)  I explained I wasn't upset with her but felt bad that she was in pain and that by making sure she drinks enough liquids and wipes well, she won't get irritated.

Any thoughts on what else I can do/another method I can teach her?