Small Fibre Neuropathy (SFN) is a type of nerve disorder resulting from damage to the peripheral nervous system, and can sometimes be a sign of an underlying health condition such as diabetes or autoimmune disease.
The small fibres of the peripheral nervous system which mediate sensations such as pain and temperature, also help to regulate the autonomic functions of the body, including the cardiovascular system and the gastrointestinal tract.
Research suggests up to 50% of people with pre-diabetes or diabetes will go on to develop small fibre neuropathy. Damage to these small fibres may remain unnoticeable for a little while, and symptoms can be mild and vague early on.
Symptoms of SFN
Many patients report symptoms in their hands and feet, including:
- Hot, burning sensations
- Prickling, tingling, pins and needles
- Electric shock, shooting or stabbing pains
- Pain evoked by light touch
Some people describe the feeling of a sock being gathered at the end of a shoe, or feeling as though they are walking on sand or pebbles. As you can see, some of these sensations are very specific and can be quite difficult to describe.
With SFN, it’s common to have reduced pain sensation in your feet and hands, and it’s also common to have a higher sensitivity to pain in general (hyperalgesia), or pain from stimuli that should not be painful. This is known as allodynia, and some examples are pain from a light touch, or pain from clothes, or bed sheets.
SFN is mainly characterised by pain in the soles of the feet or hands, which can vary depending on the time of day and may be more severe at night. Patients with SFN may also be unable to feel pain in small areas, such as the tip of a pen.
Other symptoms of SFN
Some people with SFN may also experience disturbance to their autonomic functions, including:
- Bladder or bowel problems
- Rapid heartbeat or palpitations
- Abnormal sweating which may be excessive or infrequent
- A sharp drop in blood pressure when standing up, causing dizziness or feeling faint
- Increased sensitivity to touch or temperature changes
- Dry eyes
How common is SFN?
Whilst an exact number is unknown, researchers estimate around 8% of the global population has a type of neuropathy, with roughly 5% of people living with SFN. Other types of neuropathy included in the remaining 3%, is neuropathy of the large nerve fibres.
Large fibre neuropathy is damage to the large nerve fibres which relay information to our muscles in order to control movement. These fibres also carry some messages to our brain about vibrations, touch and balance.
People with Large Fibre Neuropathy report different symptoms due to the different functions of these types of fibres. LFN tends to contribute to muscle weakness over time.
Can SFN be treated or prevented?
50% of SFN cases are idiopathic, which means the underlying cause is yet to be identified. If the cause of SFN can be established, such as diabetes related SFN, treating the underlying problem can help to improve SFN symptoms.
It is often more difficult to treat idiopathic SFN, which is why clinical research into the condition and new treatments for targeted pain management is so important.
If any type of neuropathy is left untreated, the condition can be quite dangerous. Early intervention for those able to identify the underlying cause of their neuropathy, means their outlook can be quite positive.
As the age old saying goes, prevention is better than the cure. If you lead an active, health lifestyle and aim to avoid toxins and high quantities of alcohol, you can potentially prevent developing nerve disorders like SFN.
You can read the full list of treatments for neuropathy on the NHS website. Currently, there are no effective treatments specifically for SFN, only treatments that attempt to relieve nerve pain.