Welcome to Just Answer and thanks for your question. Was your wife menopausal before the hysterectomy? Were her ovaries taken? How long has it been since the hysterectomy?
Thanks for the additional information. Hair loss from anesthesia should be over by now. It is possible that her testosterone level is too high and that is the reason for the hair loss. She may want to visit an endocrinologist or gynecologist for a reproductive hormone panel to see what her hormone levels are. After menopause, ovaries produce some hormones, but nothing like as much as they do pre-menopause. She just may be having hormone overload. There is a lot of hype about bioidentical hormones. From a biochemical standpoint there should be no difference in function, just as there is none between natural vitamins and synthetic ones. It can also be from things like thyroid hormone imbalance or stress.
That's the best idea. It is difficult to determine what is causing it without the proper tests. Good luck to you both.