Dry Skin Condition - Help!

Over the last several years the skin on the font of my arms, hands and legs is very dry and wrinkled. My GP says I look dehydrated and to use lots of moisturizers.
She says these parts of my body are not getting enough oxygen. I look like a wrinkled witch; but again only on the front of my legs arms and hands. I have had my thyroid tested 4 times in 5 years. Negative! Can anyone please cast a clue what my be causing this and what to do about it.