I am a 51 year old female who had a complete hysterectomy 10 years ago. My scalp has been itching ever since and I find hair on my pillow every morning. Fortunately, I also began with very thick hair. The itching is intense. I was diagnosed with a fragrance allergy, but using fragrance free products (everything) does not help at all. Dandruff shampoo made no difference. Prescription shampoo did not help. I hate to think I will have this condition for the rest of my life. I’ve tried cutting back on my hormone replacement hoping it would help, but it didn’t.
If I examined your scalp I might make sense of what you are telling me here, but there’s not much help I can offer you without seeing you and knowing more about your history. Just note that scratching your scalp harshly will eventually cause hair loss from traction alopecia.
Since treating a fragrance allergy didn’t resolve the itchy scalp, you should go back to your dermatologist for a follow-up. It’s possible the HRT is leading to the scalp itch, but this is something you should also be discussing with your doctor.