Briefly: Small fiber sensory neuropathy (SFSN) is a disorder in which only the small sensory cutaneous nerves are affected. The majority of patients experience sensory disturbances that start in the feet and progress upwards. These patients have what is called a lengthdependent SFSN. This type of SFSN is often due to diabetes or impaired glucose metabolism (i.e. early or pre-diabetic state) and may progress to typical diabetic polyneuropathy. However, in a significant percentage of patients, no underlying etiology is found and the patients have idiopathic SFSN. A small percentage of patients with SFSN experience sub-acute onset sensory disturbances diffusely over the whole body, including the trunk and sometimes even the face. These patients have non-length-dependent SFSN and almost all cases are idiopathic.