@adlib071 for what it's worth I experienced hair loss after my colectomy. I was 25 and had had shoulder length hair. I had lost 30 lbs in a month and was skeletal prior to the surgery.

Someone told me it's not so much that it fell out (although it did), but that stress, malnutrition, and long illness stopped the hair from growing.

Which I could see, it didn't get any longer. Eventually my hair started growing again, and new hair came in. I cut off the remaining long part and it looked a lot better.

I've had many other surgeries since then, but never experienced the dramatic hair loss.