What Causes Redness And Irritation Of Labia Minora?

my 4 year old has a clear watery discharge most days and at times it s pale yellow/white and mucousy. Her labia minora gets very red and irritated causing discomfort. She s been treated for yeast infection twice but was asymptomatic for a short period. when red and irritated I apply Prevex B 0.1% to the labia minora which helps the redness and discomfort for a few days but then the clear discharge returns & reddened/irritated peri area. appears again.also when irritated ,I notice a slight odor. what could this be ?