Uggla, I've never heard of such a thing, so I can't apply any experience. However, wikipedia lists some potential causes, and the ones that stand out to me as possibly applying are: hypoglycemia, micronutrient deficiencies, and dehydration.

So would suggest trying one of these:

1. If you test your blood sugar and it's low, I would suggest eating more frequently.

2. You could try taking electrolytes (especially potassium, and magnesium) and see if it has an effect.

3. You could just try drinking more. Dehydration is fairly common with ketosis, especially at first, because of the diuretic effect.

Interestingly, some anticonvulsants have been associated with this side-effect. Since ketosis is a potent anticonvulsant, there may be mechanisms in common. In particular, topiramate can cause it, and it has been found that supplemental potassium can relieve it. So I would try number 2. first.

Note that potassium problems can originate with magnesium deficiency, so try both. Volek and Phinney recommend taking Slow-Mag, three at bedtime for 20 days to fix a deficiency.

If you try this, please let us know whether it helped.

Is it definitely "pins and needles", or more of a twitchy, bubbly sensation? I get the latter (fasciculation according to a search I did once) fairly frequently when I go into ketosis, along with some attention-grabbing leg cramps at night. It seems to be a electrolyte imbalance issue, and making sure I'm getting enough potassium, magnesium, and salt usually makes it stop.

There are a lot of causes of paresthesia. Given that this occurs primarily when you are in ketosis, I would suggest first looking into vitamin deficiency and/or malnutrition. If this occurs regularly, you may also want to get your thyroid tested by your doctor.

I wonder if it would have anything to do with mobilizing heavy metals or other toxins from your adipose tissue stores when you are in ketosis. If it increases with higher activity levels that also makes me think it could be a "detox" thing. I think some NDs do testing for heavy metals working their way out of your system with hair analysis (although I don't know how effective the tests are).

My other thought, since you also have migraines, is that there could be some twisted muscle fibers in your neck, shoulders, or back that are pinching the nerves going down to your extremities, and the sudden loss of water weight that happens when going into ketosis could cause the muscle to tighten down further, and compress those nerves even more. You might want to get evaluated by myofascial therapist to make sure nothing is caught or twisted...and in the meantime make sure you are up on your electrolytes.

I was going to suggest thyroid, also get checked out neurologically, you don't want to ignore this kind of thing.

I asked this in the past, because I had this too. It only disappeared recently but I still occasionaly have it a bit. Using potassium helped a tiny bit, but not enough at all.

Possible causes include hypothyroidism and vitamin B5 deficiency (see here for the last one).

Since low-carbing tends to worsen hypothyroidism (though I think ketosis is better than VLC), I wouldn't low-carb for a while.