If there is ONE underlying common cause to the above conditions, of which there is an epidemic in many parts of the world, then one candidate for this common cause is a dysregulated immune response due to a imbalance in the human microbiome ( - which is not limited to the gut and GI track).
This brief article, may serve as an introduction to novices and a summary for those already familiar with this viewpoint:
huffingtonpost.com/alanna-c... - it is by no means complete, . . . . . but one starting point. In fact, I believe a whole area of knowledge has been (unwittingly or otherwise) omitted in this article, which is otherwise a good introduction to the subject.
Sid Arthur ;~))