Neuropathy or nerve damage due to diabetes can present as
insensate neuropathy (sensory loss) or painful neuropathy. The
majority of people have the insensate type. However
approximately 4-7% of patients with diabetes suffer chronic,
often distressing symptoms of pain, pins and needles or numbness
in their feet.
Why do people get painful neuropathy?
This question is yet to be fully answered and is the subject
of ongoing research. People with poorly controlled diabetes for
a long time are more likely to get chronic painful neuropathy.
However, many patients with relatively well controlled diabetes
also develop it.
Painful symptoms can be transient, eg. less than 12 months
duration. These symptoms are often associated with periods of
high blood glucose levels, or paradoxically, when the blood
glucose level rapidly improves. In these acute situations, once
the blood glucose has stabilised for a few months, the symptoms
often spontaneously disappear.
Once symptoms have persisted for more than 12 months, they
are less likely to disappear on their own. Although good blood
glucose control is important for many reasons, striving for very
tight blood glucose control is less likely to make the painful
symptoms get better when they have been present for this length
A number of theories have been suggested as to why chronic
pain or symptoms develop. It is thought that:
- high blood glucose causes changes to the nerve fibres
which results in abnormal nerve signals
- high blood glucose causes changes to blood vessels which
supply the nerves
- unknown factors release chemicals that irritate the
nerves and activate pain receptors
What type of symptoms do people get?
There is a wide variety of symptoms that people describe.
More often the feet are affected, but the legs and sometimes
hands can be involved as well.
Commonly reported symptoms include:
Burning, feeling like the feet are on fire
People with painful neuropathy may also complain of:
- Allodynia which means feeling pain from a stimulus that
would not normally be painful. An example of this is wearing
shoes or having bed sheets touching the feet
- Hyperalgaesia which means having an exaggerated response
to a stimulus which is normally painful. This is often seen
in response to heat
- a feeling of tightness or pressure around the feet
- vibration or tingling sometimes described as ants
crawling under the skin
Does the pain increase my risk of serious foot problems
Not necessarily. If you have normal sensation and good
circulation, having pain on its own will not increase your risk
of foot problems. This is important, as often just knowing this
will help to ease the distress. However, if you also have
sensory loss or poor circulation in addition to pain, your risk
of foot problems is increased and you need to take proper care
of your feet. See section on Foot Care for People with High Risk
How is it Treated?
Firstly it is important to determine if the pain is due to
diabetes or some other cause. People with pain should have a
Pain due to diabetes is usually:
- present in both feet
- of equal severity in each
- often, but not always, worse at night
If the pain is in one foot only, it is likely from another
cause such as arthritis, spinal problems, other neuropathies or
peripheral vascular disease, which should be investigated by the
appropriate medical personnel.
If diabetes is determined to be the cause, and is
sufficiently distressing to warrant treatment, there are a
number of options available. Unfortunately, neuropathic pain is
not easy to treat and not all treatments are helpful for all
people. It is important to understand that for some people,
several treatments may need to be tried or used in combination
to achieve acceptable symptom relief.
Some commonly used treatments include:
This is particularly suitable for people who do not like
It is thought to work by suppressing painful signals from
reaching the brain. More commonly these days, the treatment
involves passing a small electric current through the needles.
Cream containing Capsaicin
Capsaicin is an ingredient found in chilli peppers. It is
particularly helpful for people who experience burning pain. It
reduces pain by removing a chemical called substance P from the
nerves which is needed to transmit certain pain signals. To
achieve symptom relief, a strength of 0.075% or greater should
be used which is found in a number of preparations. The cream is
applied topically to the feet, so is also good for people who do
not like taking tablets. However, it needs to be applied several
times per day, so the person needs to be motivated to apply it
regularly, and able to reach their feet easily or have someone
available to do it for them.
It is important to note that capsaicin may cause burning or
discomfort when first applied. Treatment should persist for at
least a month to determine its effectiveness.
These agents are the tried and tested treatment for
neuropathic pain. They are helpful in many cases but their use
is often limited by side effects such as urine retention, dry
mouth and daytime drowsiness, although some newer preparations
are less likely to have these effects. They are usually taken at
night, which helps to improve sleep. They should be used in
caution with people with glaucoma or the elderly.
Antidepressants in other classes may also be proven to be
successful, but at the moment there are few scientific studies
to support their use.
Have been shown to be helpful in some people. One agent
Gabapentin, has proven to be promising but at this stage is only
allowed for treating epilepsy. A drug related to Gabapentin is
currently undergoing clinical trials. If successful, it will be
marketed for use in treating painful neuropathy.
These drugs, primarily used for regulating heartbeat or local
anaesthesia, are sometimes helpful in treating painful
neuropathy. They work by blocking the electrical conduction of
painful signals along nerve fibres. The main agent used is
Mexiletine. Its use is contraindicated in people who have an
arrhythmia, so an ECG should be performed prior to use if there
is any doubt. It is generally well tolerated but side effects
include dizziness and nausea. Sometimes people are given a test
with lignocaine, another drug in this class, to determine if
Mexiletine will be helpful in their situation.
For minor pain, simple analgesics, such as paracetamol or
aspirin are often helpful. However, until now, it has been
generally accepted that opiates or narcotic agents are not
helpful in relieving neuropathic pain. A newer non-narcotic
agent known has Tramadol, has been shown in a few small trials
to have promising results.
Chronic pain is not just a product of physical abnormalities.
Psychological factors have significant influence over how an
individual perceives and deals with pain. As such, psychological
support is integral to the treatment of chronic pain. Formal
assessment and counseling should be made available to people
who have difficulties in coping with their pain.