There is a lot of material on this site related to the appearance of DUPs or acelerated growth of DUPs due to trauma/manual work/sport etc. There does not seem to a definite answer.
Raynaud's is in my family and so is DUPs so that's intriquing. There is also a lot of hereditary stress, anxiety, Bipolar Disorder. I notice that my mood swings associated with Bipolar seem to affect my DUPs comfort and growth rate. When in a 'down phase' (depressed, anxious), the nodules hurt somewhat and grow rapidly. When in an 'up phase'(life of the party),I don't even notice the DUPs and there's no growth or in fact perhaps a slight receeding in nodule size.
I am convinced that conditions such as depression, anxiety, stress, malcontent etc. exacerbate DUPs.
What can others say about this?