Hello everyone!

I think it's finally time to make an introductory post--maybe it will help someone one day. To start, I'm a mid-30s male who has likely been dealing with some form of idiopathic SFN for the past 4 or 5 years. I had this diagnosis confirmed with a distal punch biopsy which revealed a neurite density less than the 1st percentile.

It's hard to know where my story starts, but around 5 years ago, I started noticing patches of hypersentivity/dysesthesia, mostly on my lower body. Fast forward 2 years and with these symptoms getting worse, a back injury finally has me seeing a neurologist who confirmed that my symptoms were not related to the disc bulge they found, but more imagining of my spine, an EMG, and some basic labs revealed no obvious cause of any neurological problems.

I had been attributing my symptoms to poor circulation and maybe some skin allergy/irritation. I thought it wasn't serious, until a few things happened: (1) my feet started feeling cold enough to make falling asleep hard, (2) those hypersensitive skin sensations stopped happening entirely and instead I noticed regions of skin with decreased touch and temperature sensation, (3) decreasing sexual function/sensation, (4) intermittent urinary urgency.

I started to really worry that my neurologist had been wrong about my back (or that I had some other nerve injury), and decided to see a better doctor. Another MRI revealed no changes to my back and no symptoms of nerve damage/compression. My symptoms were bilateral, so it was difficult to blame an injury anyway. A lot of labs were run over the course of a year, while my symptoms slowly get worse for no obvious reason.

The labs revealed nothing interesting besides:
High IGA
High ACE, but no other sarcoidosis symptoms
Almost-low C3/C4

Over time the urinary urgency became a decrease in urinary sensation, and the feeling of cold feet became only an abnormal sensation of temperature. Both of those changes were life-improving, but I suspect they also represented a progression of the problem. And symptom (3) has continued to have a pretty severe effect on my general quality of life.

Finally, a sweat test was abnormal and the follow-up skin biopsy was also abnormal and found a "profound reduction of innervation of epidermis and to a lesser extent, of dermal structures"). With this result, I have been lucky enough to have IVIG approved by my insurance, and I will be starting that treatment in a few weeks.

I do not know if my symptoms are caused by an autoimmune problem, but I guess I am hopeful that they are and that IVIG could make a difference. I have read that an infection can trigger autoimmune problems, and just before any of these symptoms starting, I suffered from a bad flu and subsequent pneumonia that had me feeling weak for a month. It was about two months after recovering that I distinctly remember my first experience of an abnormal skin sensation--a patch of skin on my thigh that was irritated by the fabric of my pants.