How Can Flaky Skin In The Labia Majora Causing Itching Be Treated?

My daughter is 11 years old and has had pubic hair for almost two years. Psoriasis runs in my family and I have seen evidence of a patch in her hair. For quite a while now she has shown signs of red, somewhat flaky skin on her labia majora. I believe it may be psoriasis and I would like to know how to help her treat it to relieve the itching and redness. She has not begun menstruation yet.