Just want to note that Elaine is correct about several things, but I think made a minor error in the list of initial testing. The levels tested are for 'antibodies', not auto-antibodies...and she is correct, they do include levels of IgA, IgM, IgE, and IgG (all four subclasses).

Sophie, you need to have the skin biopsy done to confirm the SFN (you don't say whether you had it or not...only that the doctor ordered it). I'd like to note that 25% of those with autoimmune disease also have immune deficiency, so this should be considered for you (testing for autoimmune disease).

If you do have SFN and found to also have an immune deficiency, then autoimmune testing should be done. IVIG can not only help the immune deficiency, but higher doses can help neuropathy (SFN) caused by autoimmune disease.

You should definitely keep this neurologist and complete the testing he ordered...but also see a hematologist or immunologist for the immune deficiency and maybe a rheumatologist if they suspect an autoimmune disease process.