There are 3 different skin conditions that can affect the vulvar (right outside the vaginal opening) area.  They are unrelated, but are treated the same.
One very common and fairly easily treated is called  LICHEN SIMPLEX CHRONICUS (LSC)  It is the same as having eczema, or an allergic reaction to a systemic or topical agent causing itching and a rash on the skin areas of the outer vulva.  Heat and sweat often make the itching way worse and there can be infections that develop from open skin scratches.  Luckily, this clears up by removing the offending agent, such as foods, pads or cleansers, and healing the skin with steroid ointments or salves.
LICHEN SCLEROSUS (LS) affects about 5% of women, is believed to be an auto-immune phenomenon, and is more difficult to treat.  The symptoms of pain, dryness, tightness, and loss of labia can be much worse if there is also lack of estrogen.  Some younger, but mostly post menopausal women are affected; it can run in families, and it is associated with other autoimmune conditions such as Hypothyroidism, etc.  The skin tends to get thick, white, waxy with red or purple dots around the clitoris and labia.  The most important reason to treat this aggressively is to prevent these abnormal cells from turning into cancer (rare, but possible).  Some herbal salves and PRP (Platelet Rich Plasma) have been helpful in treating this condition.  LS should be monitored closely with your Gynecologist and biopsied if there are any concerns.
LICHEN PLANUS (LP) is a rather rare, suspected auto-immune condition.  It causes burning, itching  and pain in the outer vaginal area, with straight reddish streaks in the inner labia.  It often has similar lacy lesions in the mouth.  It is also treated most reliably with steroid ointments and topical estrogens if needed.