What Could Cause Dry Patchy Skin?

Hi,
I have a very dry patchy skin on my face, i am facing this for past two years. 2 years ago i used LOMELLA and ADIT creams on my face for 6 months which gave me clear skin in the meanwhile it made my skin sensitive too, so i stopped using them and my skin was fine for a year after, again i was exposed to harsh australian sun which slowly gave me dry patches on my face, i tried lots of moisturisers nothing worked. my skin becomes more flacky to harsh soaps. Is there any permanent solution to get red of this dry patchy and flacky skin