For the last 5 months, I have been suffering from an itchy scalp, primarily on the crown of my head. This happened essentially overnight and after scratching for a day, I coincidentally saw that my hair had thinned slightly in those itchiest areas by the next day. I went to see a General Practioner a week or so later and I was told I had dermatitis and was told to use a Nizoral Shampoo and a Betnovate Scalp Applicator to help relieve the issue. I used them for a month and they had not helped at all. Following this, I must have seen 5 more General Practitioners and each one seemed as clueless as the last; several could not identify the problem and told me to just wait it and out because it will improve "eventually". One told me it might be a fungal issue. One said it could be stress. However, Telogen Effluvium, Psoriasis, Ring Worm, Alopecia Areata and Iron deficiency were all ruled out, however, nobody seems to have an answer for it actually is. When I have gone to the doctors, they have told me that my scalp looks perfectly healthy; I do not suffer from large oily dandruff flakes, my scalp is not red, I do not have bumps or scamps. The itchy areas are slightly more tender and sensitive than the rest of my head. If I do not moisturise my scalp for a few days then it can get dry and tiny white flakes (not oily large dandruff flakes) can be brushed out with my hands but that would happen but doctors have told me that my scalp does not look dry (most likely because I moisturise it daily with oils). I have also tried not washing my hair, using coal tar shampoo, Salicylic Acid shampoo, Sulfate free shampoos designed for dry scalp and hair oils including tree tree oil, coconut oil, olive oil, etc and even corticosteroid fungal creams. The itching is slightly better (at the moment I use Sulfate free shampoo every 3 days and moisturise my scalp daily with oils) but the itching isn't completely gone and gets worse after a few days without washing and my hair hasn't yet grown back. It is also worth noting that men in my family lose their hair much later in life, I'm in my twenties and this was overnight, not a gradual issue.
What could my issue be? Do I have hyperthyroidism? Do I need to go to a private dermatologist rather than a General Practioner?
Thanks for any help in advance