 In some instances, other health conditions cause this disorder.Diabetes mellitus and impaired glucose tolerance are the most common diseases that lead to this disorder, with 6 to 50 percent of diabetics or pre-diabetics developing small fiber neuropathy.Other causes of this condition include a metabolic disorder called Fabry disease, immune disorders such as celiac disease or Sjogren syndrome, an inflammatory condition called sarcoidosis, and human immunodeficiency virus (HIV) infection.