Possible Diet Deficiency?

Has your wife gotten all her labs done lately?? That is what is key --- getting a thorough bloodwork panel done including the b vitamins. It sounds like possibly she could have neuropathy which can result in skin sensitivity itchiness and pain or tingling. B12 could be a culprit but regardless of any speculation here she should be getting all labs done on a fairly regular basis

RLS - may also be a sign of low iron, low ferritin. 
Low proteins level - may also cause muscle weakness and issues. (I am currently on 120-160 gr protein per day - to make sure my blood work show mid normal and not low normal proteins level). 
Low level of vit B12 or B1 - may cause permanent nerve damage.  Currently I am on weekly B12 injections (pill form or liquid did not work well for me)

Skin issue  - don't let me start on that - one - Vit A deficiency, low levels of good Omega 3 may cause that. Then there is fungal - yeast issue, and last - sensitivity to artificial sweeteners (splenda, nutrasweet, etc) artificial colors and flavoring (that so many protein supplements have). I had to clean my diet, and remove most of those from my daily intake.   I developed skin issues - that goes away once I am off that stuff for a week or 2.  

And the list can go on.  Most docs do not know that. I went to a couple dermatologist and the only thing they gave me was creams and pills.    Once I discontinued the artificial stuff- and introduced extara vitamins, minerals, good oils, etc... most of my symptoms went away.  Unfortunately it is easier said than done.