During extreme stress, functions that are deemed by the body as non-essential are put on pause so we may see a reduction in energy directed towards skin repair, hair growth and even digestion. With PTSD, unfortunately the temporary reaction is prolonged, which in turn can precipitate hair loss.
I had naively assumed that my modern feminist praxis allowed me to stop caring about the way I look. Now I see that I was only enjoying having the choice not to care, which is mostly rooted in my privilege as a white woman.