I have the same problem. I use a ResMed AirFit N20 mask. The back of my scalp right about my neck itches all day. I don't have a solution so let me know if anyone has any suggestions.
I have wrapped a handkerchief about the frame of the mask that touches my face and that seems to help with the itching on my face.
I have worn a CPAP for 25 years and never had a problem. I purchased a SoClean this summer and have been using it daily. Over the past 2 months I have developed an allergic reaction to something around my nose area where my cpap mask sits and my entire nose area is red, dried out, skin cracking and bleeding. My dermatologist thinks it may be my mask, but I have using the same style mask that I have used for years. I purchased this mask also this summer as I usually replace my masks every 3 years with a new one, same company, same type of mask.
Could the So Clean unit cause what is happening to my nose ? Could the So Clean break down the composition of my mask ? My mask is a ResMed Air Fit N20 model.