"Skin writing" (dermatographia)

Hi all.

Does anyone suffer with dermatographia which shows up as red lines on the skin after using your finger nails (for example) to lightly scratch or draw lines on various parts of your body?

I do almost every day but particularly when I feel unwell or in a period when my skin itches a lot. This can be anywhere on my body and the itchy skin seems to be below the surface not on the skin itself. There's never a rash. It feels like it's in the layers below the skin and it drives me mad. I don't think it's from PMR or prednisone as I've had for years and we'll before the diagnosis. Even rubbing my chest or face for example with a bit of pressure will turn my skin red but I can sign my initials on my arm and it stays there for about a minute or so.

I know a bit about dermatographia but just wonder if anyone with PMR has it as a symptom.

Thanks in advance.