My daughter has had itchiness in her vagina, but there are no hives or anything, what could be the cause?

Vaginitis: This could be a case of vaginitis, a non-specific inflammation of the vaginal mucosa secondary to possibly hygiene issues, bacterial or yeast overgrowth. Is there discharge and what type? Has she taken a course of antibiotics recently. It may resolve by simply spending time in the bathtub with lukewarm water 3x/day for 20 minutes at a time