Painful small fiber sensory neuropathy (SFN) is relatively common and a disabling medical condition. It is the most common type of painful sensory neuropathy in patients older than 50 years of age. It is defined as a neuropathy that exclusively or predominantly affects the A-δ (small myelinated) and nociceptive C (unmyelinated) nerve fibers and their functions. The neuropathic pain associated with SFN is described by the patients as burning ("feet are on fire"), sharp ("knife-like, jabbing or pins and needles"), shooting, and aching pain in the toes and feet. The feet are described as tingling, numb, or feeling tight, wooden or dead. The pain is disabling and often exacerbated at night interfering and disrupting the sleep pattern. Allodynia and cramps may also occur. Some patients also describe pressure induced pain in their feet with standing and walking. The autonomic nerves may be involved leading to increased or decreased sweating, facial flushing, skin discoloration and erectile dysfunction in up to 40% of males. On examination there is a dramatic mismatch between the symptoms and observable deficits in SFN. Only abnormal findings are the loss of pinprick and temperature sensations in feet that may extend up to the knees. Touch sensation may be diminished but other sensations are usually preserved. By definition, patients with SFN are allowed to have minor involvement of large fibers distally with reduced vibration in toes but the ankle reflexes are usually preserved.