Pigmented Knuckles, Autoimmune Disease?

18 month ago I noticed my hairline was receding and took propecia accordingly.

6 month later I began to notice that the hair on my arms, legs, eyebrowns, and in the public region were thinning. At 12 months, I began to notice pigmentation on my knuckles and small bumps on my nails – even sore joints – all signs of an autoimmune disorder.

I’ve noticed anecdotal evidence on the web that this can happen.
Is there further evidence to support this?

Autoimmune diseases can attack any organ in your body, including your hair. If you think that you have an autoimmune disease and there are many skin pigmentation changes, see a good dermatologist first. What you are describing is outside of my area of expertise.