Peripheral neuropathy is a term for a group of conditions in which the peripheral nervous system is damaged.
The peripheral nervous system is the network of nerves that lie outside the central nervous system (the brain and spinal cord).
It includes different types of nerves with their own specific functions, including:
sensory nerves – responsible for transmitting sensations, such as pain and touch
motor nerves – responsible for controlling muscles
autonomic nerves – responsible for regulating automatic functions of the body, such as blood pressure and bladder function
Signs and symptoms
Damage to the peripheral nerves can cause a wide range of symptoms depending on the specific nerves affected.
In many cases, the condition first develops in the extremities of the body, such as the feet, hands, legs and arms.
The main symptoms of peripheral neuropathy can include:
numbness and tingling in the feet or hands
burning, stabbing or shooting pain in affected areas
loss of balance and co-ordination
muscle weakness, especially in the feet
These symptoms are usually constant, but may fluctuate.
Generally, the sooner peripheral neuropathy is diagnosed, the better the chance of limiting the damage and preventing further complications. It's therefore important to see a GP if you experience symptoms of peripheral neuropathy.
What causes peripheral neuropathy?
In the UK, diabetes (both type 1 and type 2) is the most common cause of peripheral neuropathy.
Over time, the high blood sugar levels associated with diabetes can damage the nerves. This type of nerve damage is known as diabetic polyneuropathy.
Peripheral neuropathy can also have a wide range of other causes. For example, it can be caused by physical injury to the nerves, a viral infection such as shingles, or as a side effect of certain medications.
People who are known to be at an increased risk of peripheral neuropathy may have regular check-ups so their nerve function can be assessed.
Who is affected?
Peripheral neuropathy is a relatively common condition that affects around 1 in 50 people in the UK. The condition becomes more common as you get older, and has been estimated to affect almost 1 in every 10 people who are 55 or over to some degree.
How peripheral neuropathy is treated
Treatment for peripheral neuropathy depends on the underlying cause and the type of symptoms you are experiencing.
Only some of the underlying causes of neuropathy can be treated. For example, if you have diabetes, controlling your blood sugar better, stopping smoking and cutting down on alcohol may help.
Nerve pain may be treated with special prescribed medication as standard painkillers don't usually work.
If you have other symptoms associated with peripheral neuropathy, these may need to be treated individually. For example, treatment for muscle weakness may involve physiotherapy and the use of walking aids.
If peripheral neuropathy affects the nerves controlling the automatic functions of the heart and circulation system (cardiovascular autonomic neuropathy), you may need treatment to increase your blood pressure, or possibly a pacemaker.
The outlook for peripheral neuropathy varies, depending on the underlying cause and which nerves have been damaged.
Some cases may improve with time if the underlying cause is treated, whereas for some people the damage may be permanent or may get gradually worse with time.
In cases of peripheral neuropathy caused by diabetes, bringing your diabetes under better control can help prevent further nerve damage and may help improve your existing symptoms.
If the underlying cause of peripheral neuropathy is not treated, you may be at risk of developing potentially serious complications, such as a foot ulcer that becomes infected.
This can lead to gangrene (tissue death) if untreated, and in severe cases may mean the affected foot has to be amputated.
Electron micrograph of a section through nerve tissue, showing peripheral neuropathy or nerve damage
Peripheral neuropathy and polyneuropathy
Peripheral neuropathy may affect only one nerve (mononeuropathy), several nerves (mononeuritis multiplex), or all the nerves in the body longer than a certain length (polyneuropathy).
Polyneuropathy is the most common type and starts by affecting the longest nerves first, so typically begins in the feet. Over time it gradually starts to affect shorter nerves so feels as if it is spreading upwards, and later affects the hands.
Symptoms of peripheral neuropathy
Depending on the cause of the peripheral neuropathy, symptoms may develop slowly or quickly.
The specific symptoms of peripheral neuropathy vary according to the type of peripheral neuropathy you have. There are three main types:
sensory neuropathy affects the nerves that carry messages of touch, temperature, pain and other sensations to the brain
motor neuropathy affects the nerves that control movement
autonomic neuropathy affects the nerves that control involuntary bodily processes, such as digestion and your heartbeat
In many cases, someone with peripheral neuropathy may have more than one of these types of neuropathy at the same time.
In particular, a combination of sensory and motor neuropathy is common. This is called sensorimotor polyneuropathy.
The symptoms of the main types of peripheral neuropathy are described below.
Symptoms of sensory neuropathy can include:
prickling and tingling sensation in the affected body part (pins and needles)
numbness and a reduced ability to feel pain or changes in temperature, particularly in your feet
a burning or sharp pain, usually in the feet and legs
feeling pain from something that should not be painful at all, such as a very light touch (allodynia)
loss of balance or co-ordination
Symptoms of motor neuropathy can include:
twitching and muscle cramps
muscle weakness or paralysis affecting one or more muscles
thinning (wasting) of muscles
foot drop (difficulty lifting up the front part of your foot and toes, particularly noticeable when walking)
Damage to the autonomic nerves can result in a wide range of symptoms depending on where in the body the damage occurs.
Symptoms of autonomic neuropathy can include:
constipation or diarrhoea, particularly at night
feeling sick, bloating and belching
low blood pressure (postural or orthostatic hypotension), which can make you feel faint or dizzy when standing up
rapid heartbeat (tachycardia)
excessive sweating or a lack of sweating
problems with sexual function, such as erectile dysfunction in men
difficulty fully emptying your bladder of urine
bowel incontinence (loss of bowel control)
problems swallowing (dysphagia)
Depending on the specific nerve affected, symptoms of mononeuropathy can include:
altered sensation or weakness in the fingers
double vision or other problems with focusing your eyes, sometimes with eye pain
weakness of one side of your face (Bell's palsy)
foot or shin pain, weakness or altered sensation
The most common type of mononeuropathy is carpal tunnel syndrome (CTS). The carpal tunnel is a small tunnel in your wrist. In CTS, the median nerve becomes compressed where it passes through this tunnel. This may cause tingling, pain or numbness in the fingers.
When to seek medical advice
Generally, the sooner peripheral neuropathy is diagnosed, the better the chance of limiting the damage. It is therefore important to remain alert for the early signs and symptoms of peripheral neuropathy, such as:
pain, tingling or loss of sensation in the feet
loss of balance
a cut or ulcer on your foot that is not getting better
changes in your normal bowel and bladder functions, such as persistent diarrhoea or constipation
faintness on standing up
See your GP if you experience the above signs and symptoms.
It is also recommended that people with risk factors for peripheral neuropathy, such as diabetes, have regular check-ups.
Causes of peripheral neuropathy
Diabetes is the most common cause of peripheral neuropathy in the UK.
Neuropathy can also be caused by other health conditions and certain medications, although in some cases no cause is identified.
Neuropathy caused by diabetes is called diabetic polyneuropathy. It's estimated around 60% of people with diabetes are susceptible to peripheral neuropathy and up to one in every four people with the condition have experienced some pain caused by nerve damage.
Peripheral neuropathy can be caused by either type 1 diabetes or type 2 diabetes, and becomes more likely the longer you have had diabetes.
If you have diabetes, your risk of polyneuropathy is higher if your blood sugar is poorly controlled or you:
have high blood pressure (hypertension)
regularly consume large amounts of alcohol
are over 40 years old
It's thought diabetes leads to peripheral neuropathy because the high levels of glucose in your blood damage the blood vessels that supply your nerves.
If you have diabetes, your feet will usually be examined at least once a year to check for ulcers (open wounds or sores) as well as signs of possible nerve damage, such as reduced sensation.
As well as diabetes, there are many other possible causes of peripheral neuropathy. If no cause is found, it is called an idiopathic neuropathy.
Some of the health conditions that can cause peripheral neuropathy include:
excessive alcohol drinking for years
low levels of vitamin B12 or other vitamins
physical damage to the nerves, such as from an injury or during surgery
an underactive thyroid gland (hypothyroidism)
certain infections, such as shingles, Lyme disease, diphtheria,botulism and HIV
inflammation of the blood vessels (vasculitis)
chronic liver disease
chronic kidney disease
monoclonal gammopathy of undetermined significance (MGUS) – the presence of an abnormal protein in the blood
certain types of cancer, such as lymphoma (a cancer of the lymphatic system) and multiple myeloma (a type of bone marrow cancer)
Charcot-Marie-Tooth (CMT) disease and other types of hereditary motor sensory neuropathy – genetic conditions that cause nerve damage, particularly in the feet
having high levels of toxins in your body, such as arsenic, lead or mercury
Guillain-Barré syndrome – a rare condition that causes rapid onset of paralysis within days
amyloidosis – a group of rare but serious conditions caused by deposits of abnormal protein called amyloid in tissues and organs throughout the body
conditions caused by overactivity of the immune system, such asrheumatoid arthritis, lupus or Sjogren's syndrome
A few medications may sometimes cause peripheral neuropathy as a side effect in some people. These include:
some types of chemotherapy for cancer (especially for bowel cancer, lymphoma or myeloma)
some antibiotics, if taken for months (metronidazole, nitrofurantoin)
phenytoin (a medication used to treat epilepsy), if taken for years
amiodarone and thalidomide
Diagnosing peripheral neuropathy
A number of tests can be used to diagnose peripheral neuropathy and any underlying cause.
A doctor will ask about your symptoms and examine the affected area of your body. This may involve testing sensation, strength and reflexes.
Your doctor may then arrange blood tests, especially to check for diabetes and vitamin B12 deficiency.
Confirming if you have a neuropathy
some people may need to see a neurologist (a specialist in conditions affecting the nervous system) at a hospital appointment and have more specialised tests, such as a nerve conduction test and electromyography (EMG).
During a nerve conduction test, small metal wires called electrodes are placed on your skin. The electrodes release tiny electric shocks that stimulate your nerves. The speed and strength of the nerve signal is measured. An unusually slow or weak signal could indicate peripheral neuropathy.
EMG involves having a small needle inserted through your skin into your muscle. The needle is used to measure the electrical activity of your muscles.
Both types of test are usually carried out at the same time.
Identifying the cause of a neuropathy
Identifying the underlying cause of a peripheral neuropathy is often straightforward and can be done by your GP.
If diabetes is suspected, a diagnosis can usually be confidentially made by asking you about your symptoms, carrying out a physical examination and checking the levels of glucose in your blood and urine.
If you are taking a medication known to cause peripheral neuropathy, temporarily stopping or reducing your dose to see whether your symptoms improve may help confirm whether the medication is responsible.
If the cause is uncertain, you may be referred to a neurologist for a series of more extensive blood tests to check:
whether you have an infection that may be responsible
how well your liver and kidneys are working
the levels of nutrients in your blood, such as vitamin B12
whether you have a genetic abnormality, such as Charcot-Marie-Tooth disease
You may need a lumbar puncture to test the cerebrospinal fluid (a clear, colourless fluid that surrounds and supports the brain and spinal cord) for inflammation.
Occasionally, a nerve biopsy may be carried out as part of your diagnosis. This is a minor surgical procedure where a small sample of a peripheral nerve is removed from near your ankle so it can be examined under a microscope.
It is then checked for changes that could be a sign of certain types of peripheral neuropathy. However, nerve biopsies are rarely needed.
You may also need an X-ray, a computerised tomography (CT) scan or a magnetic resonance imaging (MRI) scan to look for any underlying cause of your neuropathy.
Treating peripheral neuropathy
Treatment for peripheral neuropathy may include treating any underlying cause and any symptoms you are experiencing.
How successful treatment will be depends on the underlying cause. For example, in peripheral neuropathy caused by diabetes, ensuring your diabetes is well controlled may help improve neuropathy or at least stop it getting worse.
Treating the underlying cause
There are many different possible causes of peripheral neuropathy, some of which can be treated in different ways. For example:
diabetes can sometimes be controlled by making healthy lifestyle changes, such as stopping smoking, cutting down on your alcohol consumption, maintaining a healthy weight and exercising regularly
vitamin B12 deficiency can be treated with B12 injections or tablets
peripheral neuropathy caused by a medication you are taking may improve if the medication is stopped
Some less common types of peripheral neuropathy may be treated with medication such as corticosteroids (powerful anti-inflammatory medication), immunosuppressants (medications that reduce the activity of the immune system), or injections of immunoglobulin (a mixture of blood proteins called antibodies made by the immune system).
However, the underlying cause may not always be untreatable.
Relieving nerve pain
You may also require medication to treat any nerve pain you are experiencing. The medical term for nerve pain is neuropathic pain.
Unlike most other types of pain, neuropathic pain does not usually get better with common painkillers, such as paracetamol and ibuprofen. Alternative medications are therefore usually required.
These should usually be started at the minimum dose, with the dose gradually increased until you notice an effect. The ideal dose for each person is unpredictable, so needs trial and error. Higher doses are more likely to help your pain, but are also more likely to cause side effects.
The most common side effects are tiredness, dizziness or feeling "drunk". If you get these, it may be necessary to reduce your dose. Do not drive or operate machinery if you experience drowsiness or blurred vision. You also may become more sensitive to the effects of alcohol.
The side effects should improve after a week or two as your body gets used to the medication. However, if your side effects continue, tell your GP as it may be possible to change to a different medication that suits you better. Many people find the first medication they try does not suit them, so they need to try others.
Many of these medications may also be used for treating other conditions, such as depression, epilepsy, anxiety or headaches. If you are given an "antidepressant", this may treat pain even if you are not depressed and does not mean your doctor suspects you are depressed.
The main medications recommended for neuropathic pain include:
amitriptyline – this is also used for treatment of headachesand depression
duloxetine – this is also used for treatment of bladder problems and depression
pregabalin and gabapentin – these are also used to treatepilepsy, headaches or anxiety
There are also some additional medications that can be used to relieve pain in a specific area of the body or to relieve particularly severe pain for short periods. These are described below.
If your pain is confined to a particular area of your body and you can't, or prefer not to, take the medications above, you may benefit from using capsaicin cream.
Capsaicin is the substance that makes chilli peppers hot and is thought to work in neuropathic pain by stopping the nerves sending pain messages to the brain.
A pea-sized amount of capsaicin cream is rubbed on the painful area of skin three or four times a day.
Side effects of capsaicin cream can include skin irritation and a burning sensation in the treated area when you first start treatment.
Do not use capsaicin cream on broken or inflamed skin and always wash your hands after applying it.
This is a large sticking plaster that contains a local anaesthetic. It is useful when pain affects only a small area of skin. It is stuck over the area of painful skin and the local anaesthetic is absorbed into the skin that is covered.
Tramadol is a powerful painkiller related to morphine that can be used to treat neuropathic pain that does not respond to other treatments your GP can prescribe.
Like all opioids, tramadol can be addictive if it is taken for a long time. It will therefore usually only be prescribed for a short time. If your pain fluctuates in severity, tramadol can be useful to take at times when your pain is worse.
Common side effects of tramadol include:
feeling sick or vomiting
Treating other symptoms
In addition to treating pain, you may also require treatment to help you manage other symptoms you are experiencing as a result of peripheral neuropathy.
For example, if you have muscle weakness, you may need to have physiotherapy to learn exercises to improve your muscle strength. You may also need to wear splints to support weak ankles or use walking aids to help you get around.
Other problems associated with peripheral neuropathy, such as erectile dysfunction, constipation, or the slow movement of food through your stomach (gastroparesis), may be treatable with medication.
In some cases, you may need more invasive treatment, such as botulinum toxin injections for hyperhidrosis or urinary catheterisation if you have problems emptying your bladder.
Complications of peripheral neuropathy
Peripheral neuropathy can sometimes cause other medical problems.
These vary depending on the underlying cause of the condition, and can include foot ulcers and disturbances to the blood circulation and heartbeat.
Diabetic foot ulcer
A diabetic foot ulcer is an open wound or sore on the skin that is slow to heal. These are common in people with diabetic polyneuropathy.
If you have numb feet, it is easy to cut your foot by treading on something sharp.
An ulcer can also occur if you unknowingly develop a blister caused by badly fitting shoes. If you do not feel any pain, you may continue walking without protecting the blister. If the cut or blister gets worse, it may develop into an ulcer.
High blood sugar can damage your blood vessels, causing the blood supply to your feet to become restricted. A reduced blood supply to the skin on your feet means it receives a lower number of infection-fighting cells, which can mean wounds take longer to heal and can lead to gangrene.
If you do develop a wound infection in one of your feet as a result of peripheral neuropathy, there is a risk this could lead togangrene (death of part of the skin or underlying tissues).
If gangrene does develop, you may need surgery to remove the damaged tissue (known as debridement) and antibiotics to treat any underlying infection, and in severe cases your toe or foot may need to be amputated.
If you have diabetes, you should take extra care of your feet. Get your feet checked regularly by a podiatrist (a medical professional, also known as a chiropodist, who specialises in foot care).
Cardiovascular autonomic neuropathy (CAN)
Cardiovascular autonomic neuropathy (CAN) is another potentially serious problem that is common in people with diabetic polyneuropathy.
CAN occurs when damage to the peripheral nerves disrupts the automatic functions that control your blood circulation and heartbeat.
The two main noticeable symptoms of CAN are an inability to exercise for more than a very short period of time and orthostatic hypotension (a type of low blood pressure that can make you feel dizzy or faint when you stand up).
You may be able to control the symptoms of orthostatic hypotension by using a number of self care techniques, such as:
standing or sitting up slowly and gradually
drinking plenty of fluids to increase the volume of your blood and raise your blood pressure
wearing compression stockings to help prevent blood falling back down into your legs
tilting your bed by raising it at the head end
In some cases, medication may be required to treat orthostatic hypotension. Two widely used medications are fludrocortisone, which works by increasing the volume of your blood, and midodrine, which works by tightening your blood vessels.
A more serious concern with CAN is that your heart may suddenly develop an abnormal pattern of beating (arrhythmia), which could lead to a cardiac arrest, where your heart stops beating altogether.
To prevent this, you may be prescribed medication to help regulate the beating of your heart, such as flecainide, beta-blockers or amiodarone.
If you have CAN, you will probably need to have regular check-ups so your heart function can be monitored.