I agree and said earlier that it works by modulating the immune system...so if there is nothing wrong with your immune system, then I don't see how it would help basic SFN (not immune mediated SFN).

IVIG carries risk and side-effects...many severe. It's not a first line treatment. Steroids should be tried first....it will at least tell you if your SFN is inflammatory based. Steroids will help (even if just a little), if it is.

You really need a skin biopsy just to confirm the SFN. I thought you already had this done. Hopefully this test will give you more information about your condition and severity. Not all skin biopsies check for morphology (actual condition of the fibers). This is important, if you get the opportunity, ask for this to be done.