I have been to my obgyn four times and I have been tested for every STD, bacterial infection, and yeast infections. They were are negative. But I still have this constant itch on the outside of vagina. I use all sensitive skin products. I don't have a foul oder or discharge, but it won't stop itching. Please help me. Im becoming depressed from it. This has been occurring for five months. Do i need to see a dermatologist? Can you tell me what may be wrong?