Alt 57 for 2 yr. other lft normal. bmi 28, no fatty liver, ana & hbsag -ve. no meds. f/h dm & psoriasis. dark faeces, joint pain. what's causing this?

Joint swelling?: If you have joint swelling you might have arthritis. Are both the Hepatitis B and C panel completely negative? The dark feces needs to be evaluated for bleeding - blood in the stomach can turn black and look like tar. Psoriasis can cause arthritis but I can not be certain that this is psoriatic arthritis. You need to see your physician and even consider a liver biopsy since ALT ^ 2 YRS.