5 year old girl constant private area rashes

Sa

My 5 year old was always prone to diaper rashes, despite quick changes and making sure she was dry. For that reason we had her completely potty trained by 2 so she didn’t need diapers anymore. Then she continued to get rashes on her vagina and butthole. I find myself putting more rash cream on her than her baby sister. I know her current rashes are not due to not wiping because I still wipe her to ensure it’s done right. I’d like to add, she a lot of the time is stinky down there. Doesn’t matter how often she’s bathed. She also does not get washed with harsh body washes, nor have bubble baths.

This morning she woke up saying her butt hurts so I looked and yup red again but it had tiny white pimples around her butthole. I’m going to make her an appointment today because it just feels like this is happening more and more often. But she’s a very private girl, and I’m not sure she’ll even let the doctor look at it.

Has anyone else’s kiddo dealt with this? I feel so bad because she’s ALWAYS complaining of it hurting. Desitin helps create a barrier so it doesn’t hurt but it doesn’t keep it from getting a rash. Should I stop washing her underwear with harsh detergents and just hand wash with mild soap?

Also I have talked to her doctor about it at yearly check ups before and she didn’t seem worried and said to just put diaper rash cream on it.

She starts school in 5 weeks and I really don’t want to send her to school with an achy butt..