I get itchy skin too with no rash or dryness! Just out of the blue will suddenly get itchy! Many people with auto-immune disorders get this from time to time. A doctor once told me that people with auto-immune disorders can release to many hystimines in their body sometimes causing the itching. It’s an allergy to your own body. Shingles is not only a part of GBS but people with Lupus get Shingles. I think it has something to do with us having auto-immune disorder which makes us more likely to catch it easier. Shingles though itches to a degree but is more painful to the nerves than anything else.
I too have told my doctor about the itching skin. I take benydrl for mine when it starts and that now helps. It’s weird how the itching starts too! It’s like you developed the instant hive and start digging! Hope it goes away soon for ya! Been there! Keep benedryl in my house now!