My 1 year old has a very bad rash down there that is starting to blister and it's itchy. i've tried creams etc. what could it be? she is seeing a doc.

Diaper rashes, yeast: Children are prone to yeast infections in the diaper region as a result of illness, recent antibiotic use, frequent diarrhea or chronic moisture under the diaper or underwear. Its usually appears as red itchy bumps, occassionally with fissures, inflammation and tenderness. These rashes frequently resolve with topical antifungal creams, if treated until gone plus three more days.