I am a 35 year old male and over the last month I have had a sudden increase growth in arm hairs. They have literally grown to at least 4 or 5 times their usual length and they are growing straight out (not flat against the skin). I have also had hairs starting to grow in places I have never had before such as on my back and shoulders
-related causes include adrenocortical disorders. It may also be due to insulin resistance and androgen excess.
A number of investigations like testosterone and ACTH need to be done to confirm the diagnosis. I suggest you to consult an endocrinologist and get it evaluated.
I hope it helps. Take care and regards.