My neuro suggested IVIG right after I got a positive skin biopsy for SFN. I don't have a specific autoimmune diagnosis and I am still struggling with the HMO to get the IVIG.

If you already have a definite diagnosis of autoimmune disorder it might be easier to justify IVIG without doing more tests.

The bureaucracy took some time, my neuro asked me to fill some forms and they searched for papers supporting IVIG for SFN in autoimmune disorders.

Good luck!