I found an amazing article which supports most of what I've read on this board including your advice, Mrs.D, and could explain my skin temperature problems:

CFS - The Central Cause: Mitochondrial Failure

. . .

"The job of the heart is to maintain blood pressure. If the blood pressure falls, organs start to fail. If the heart is working inadequately as a pump then the only way blood pressure can be sustained is by shutting down blood supply to organs. Organs are shut down in terms of priority, i.e. the skin first. . . this creates further problems for the body in terms of toxic overload. . .

Effects on the Skin

"If you shut down the blood supply to the skin, this has two main effects. The first is that the skin is responsible for controlling the temperature of the body. This means that CFS patients become intolerant of heat.

"If the body gets too hot then it cannot lose heat through the skin (because it has no blood supply) and the core temperature increases.

"The only way the body can compensate for this is by switching off the thyroid gland (which is responsible for the level of metabolic activity in the body and hence heat generation) and so one gets a compensatory underactive thyroid. This alone worsens the problems of fatigue.

"The second problem is that if the micro-circulation in the skin is shut down, then the body cannot sweat. This is a major way through which toxins, particularly heavy metals, pesticides and volatile organic compounds are excreted. Therefore the CFS sufferer's body is much better at accumulating toxins, which of course further damage mitochondria."

http://www.drmyhill.co.uk/wiki/CFS_-...ndrial_Failure

That explains why I and other people with PN don't sweat properly. It may also hint at a possible cause of PN - the skin is the first target/most vulnerable to mito failure.

The entire article is well-written and it helped me a lot.

I hope I'm on the right track... I didn't want to assume hypothyroidism is my problem until my mitochondria has been tested. This is the second (or third) doctor I've found who says your thyroid could be alright, just partly inactive due to mito issues.