I had only been taking MTX for about 2 months and had to stop due to extreme sun-sensitivity that started on the same week that I went from 10mg/wk to 15. It is now 9 months later and I cannot tolerate ANY sun on my neck and shoulders. I even get a reaction through glass (indicates UVA sensitivity). My doctors think that my problem cannot be from the MTX because I have not been taking it long enough and too much time has passed. I live in Hawaii and have done so for most of my life and never had this problem with the sun before.