Hi @emaddox Relentless itching is the worst, isn’t it? I can tolerate pain over itching any day. Unfortunately, itching can be a common side effect of having a blood cancer/blood conditions due to inflammation, which can trigger an immune response to release more histamines…causing itching.

In your case, you were diagnosed Myelodysplastic syndromes (MDS) which are a group of bone marrow diseases. I’ve posted a link below with a pretty good article explaining MDS.
This condition may be the culprit in your itching and you were on the right track with taking an antihistamine. I had to use them daily for a while. My hematologist suggested Claritin. (Avoid any that have a decongestant because that can raise BP) There are a number of over the counter antihistamines that work to quell the itch.
You will need to check with your ophthalmologist to see which antihistamines are safe for you but from my understanding, phenylephrine can be the culprit for elevating eye pressure because it can act as a vasoconstrictor. So avoiding products with that ingredient might be helpful. Again, check with your eye doctor.

Here’s the link for MDS
https://www.verywellhealth.com/what-are-myelodysplastic-syndromes-mds-2252548.
Another useful article as to why cancer can cause itchy skin.
When Is Itchy Skin a Cancer Symptom?
https://www.verywellhealth.com/is-itchy-skin-a-cancer-symptom-4582580
~Allergy meds:
https://www.everydayhealth.com/news/allergy-medicines-can-harmful-your-heart/.
You mentioned you were diagnosed with MDS last year. Were you tested for any cell mutations? How often do you have bloodwork done?