What Causes Itching Sensation And Discomfort Around Vaginal Area?

Hi, for a month now I ve been experiencing discomfort and itching externally around my vagina, the itching occurs mostly after a small amount of clear/white watery discharge which has no oder or sometimes smells slightly acidic. Also my labia majora and the external skin where the pubic hair grows have been very red and slightly inflamed and the skin feels tender to touch. Up until a month ago I always shaved or waxed all of my pubic hair but stopped as soon as I noticed the irritated skin and have not removed hair since. I have been to see a doctor three times, first they said it was thrush and gave me a pessary and cream which did nothing to help the symptoms, second time I went back and it was diagnosed as dermatitis and I was given steroid cream which again did not help. Third time I did a swab test to check for bacterial infection or thrush infection and the results were negative for both. I have also had a full GUM STI check recently (Chlamydia, HIV, Gonorrhea and syphilis) which I did not have and have not had sexual intercourse since the GUM test. I m really confused as to what could be causing this problem, it s very irritating and I m going travelling in a months time and would like to get to the bottom of this before I go!