What is Small Fiber Neuropathy
Small fiber neuropathy is a condition, where the small fibers of the peripheral nervous system are damaged. These fibers are responsible for transferring information about pain and temperature in the skin. In the other organs, the peripheral nerve fibers regulate autonomic functions, such as heart rate and breathing.
Small fiber neuropathy is characterized by severe pain attacks that typically begin in the feet or hands. People suffering from this condition cannot feel pain that is concentrated in a very small area, such as pain from a pin prick. On the other hand, they experience an increased sensitivity to pain in general (a condition called hyperalgesia) and pain from stimuli that normally does not cause pain (a condition called allodynia). Individuals affected with small fiber neuropathy may also have a reduced ability to differentiate between cold and hot. However, in some people, the pain attacks are triggered by cold or warm stimuli.
What are symptoms of small fiber neuropathy?
The signs and symptoms of small fiber neuropathy usually begin in adolescence to mid-adulthood. Symptoms of small fiber neuropathy can vary, but pain is the most common symptom. Other symptoms are:
- Burning and/or stabbing pain
- Prickling and/or tingling sensation
- Short bursts of pain
- Loss of sensation
These symptoms can be mild or severe. In some cases, external triggers may cause sensory symptoms, such as individuals might experience foot pain when wearing socks. Besides, small fiber neuropathy may also disrupt autonomic functions, which are essential for normal body functions, such as regulating digestion, blood pressure and urinary function. In case the autonomic nerve fibers are affected, the individuals will experience following symptoms:
- Difficulty sweating
- Dry eyes
- Dry mouth
- Sexual dysfunction
- Skin discoloring
What causes small fiber neuropathy?
Usually, diabetes or prediabetes are the underlying conditions causing small fiber neuropathy. However, the cause of small fiber neuropathy can also be unknown, and in such case the condition is called idiopathic small fiber neuropathy. Mutations in the SCN9A and SCN10A genes are also associated with developing small fiber neuropathy. These genes carry instructions for making sodium channels, which cells use to produce and transmit electrical signals. There are a number of other conditions, which seem to be related to developing small fiber neuropathy. These include:
- Metabolic syndrome
- Celiac disease
- Sjogren’s syndrome
- Primary systemic amyloidosis
- Familial amyloidosis
- Inflammatory bowel disease
- Infectious disease
- Hepatitis C
- Lyme disease
- Immune system disorders
What is the treatment of small fiber neuropathy?
The treatment of small fiber neuropathy depends on the underlying condition. The condition itself cannot be cured but by treating the symptoms caused by the underlying condition, the disease progression will be slowed down. For individuals with diabetes or metabolic disorders, the treatment will be managing blood glucose levels, maintaining a moderate body weight and eating a healthful and balanced diet.
In case the cause of small fiber neuropathy has not been identified, treatment focuses on managing pain-related symptoms, which are typically treated with following medication:
- Topical pain creams