Dysesthesia comes from the Greek word "dys", meaning "not-normal" and "aesthesis", which
means "sensation".
It is defined as an unpleasant, abnormal sense of touch.
It often presents as pain but may also present as an inappropriate, but not discomforting,
sensation.
It is caused by lesions of the nervous system, peripheral or central, and it involves sensations,
whether spontaneous or evoked, such as burning, wetness, itching, electric shock, and pins
and needles.
Dysesthesia can include sensations in any bodily tissue, including most often the mouth,
scalp, skin, or legs.
It is sometimes described as feeling like acid under the skin.
Burning dysesthesia might accurately reflect an acidotic state in the synapses and perineural
space.
Some ion channels will open to a low pH, and the acid sensing ion channel has been shown
to open at body temperature, in a model of nerve injury pain.
Inappropriate, spontaneous firing in pain receptors has also been implicated as a cause
of dysesthesia.
Patients suffering from dysesthesia can become incapacitated with pain, despite no apparent
damage to the skin or other tissue.
Patients suffering from dysesthesia also often suffer from psychological disorders.
Types of dysesthesia Dysesthesia can generally be described as
a class of neurological disorders.
It can be further classified depending on where it manifests in the body, and by the
type of sensation that it provokes.
Cutaneous dysesthesia is characterized by discomfort or pain from touch to the skin
by normal stimuli, including clothing.
The unpleasantness can range from a mild tingling to blunt, incapacitating pain.
Scalp dysesthesia is characterized by pain or burning sensations on or under the surface
of the cranial skin.
Scalp dysesthesia may also present as excessive itching of the scalp.
Occlusal dysesthesia, or "phantom bite," is characterized by the feeling of That the bite
is "out of place" despite any apparent damage or instability to dental or oromaxillofacial
structures or tissue.
Phantom bite often presents in patients that have undergone otherwise routine dental procedures.
Short of compassionate counseling, evidence for effective treatment regimes is lacking.
Causes Dysesthesia is commonly seen in diabetic patients,
and can be relieved by using creams containing capsaicin.
Dysesthesia may be seen in patients suffering from Guillain–Barré syndrome.
Dysesthesia is among symptoms of neuropathy.
Dysesthesia, along with polyneuropathy can be a symptom of nerve damage caused by Lyme
Disease.
The dysesthetic sensations continue after the successful antibiotic treatment of Lyme
disease.
Dysesthesia is a common symptom of a withdrawal from alcohol or other drugs.
Dysesthesia is also a common symptom of Multiple Sclerosis, or MS.
It is an effect of spinal cord injury.
Many patients suffering from occlusal dysesthesia have reported recent oral surgery before the
onset of dysesthetic pain.
Late-onset GM2 gangliosidosis may also present as burning dysesthesia.
Chemotherapy-induced peripheral neuropathy is a progressive, enduring and often irreversible
tingling numbness, intense pain, and hypersensitivity to cold, beginning in the hands and feet and
sometimes involving the arms and legs caused by some chemotherapy agents.
Dysesthesia may be caused by a thalamic stroke involving the ventral postero-lateral nucleus.
It's typically seen in Dejerine-Roussy syndrome with hemi-sensory loss and severe dysesthesia
of the affected area.
Comparison to phantom limb and other disorders Although dysesthesia is similar to phantom
limb syndrome, they should not be confused.
In phantom limb, the sensation is present in an amputated or absent limb, while dysesthesia
refers to discomfort or pain in a tissue that has not been removed or amputated.
The dysesthetic tissue may also not be part of a limb, but part of the body, such as the
abdomen.
The majority of individuals with both phantom limb and dysesthesia experience painful sensations.
Phantom pain refers to dysesthetic feelings in individuals who are paralyzed or who were
born without limbs.
It is caused by the improper innervation of the missing limbs by the nerves that would
normally innervate the limb.
Dysesthesia is caused by damage to the nerves themselves, rather than by an innervation
of absent tissue.
Dysesthesia should not be confused with anesthesia or hypesthesia, which refer to a loss of sensation,
or paresthesia which refers to a distorted sensation.
Dysesthesia is distinct in that it can, but not necessarily, refer to spontaneous sensations
in the absence of stimuli.
In the case of an evoked dysesthetic sensation, such as by the touch of clothing, the sensation
is characterized not simply by an exaggeration of the feeling, but rather by a completely
inappropriate sensation such as burning.
Recent research There are a number of hypotheses regarding
the basis of occlusal dysesthesia.
Some researchers believe the disorder is a psychological one, while others believe it
to be a psychosomatic disorder.
Joseph Marbach hypothesized that the symptoms were rooted in psychiatric disorders.
Marbach suggested that occlusal dysesthesia would occur in patients with underlying psychological
problems after having undergone dental treatment.
More recently, two studies have found that occlusal dysesthesia is associated with somatoform
disorders in which the patients obsess over the oral sensations.
Similarly, Marbach later proposed that occlusal dysesthesia may be caused by the brain “talking
to itself,” causing abnormal oral sensations in the absence of external stimuli.
According to this model, the symptoms of dysesthesia are catalyzed by dental “amputation,”
for example the extraction of a tooth, whereby the brain loses the ability to distinguish
between its memory of the bite and the actual, new bite.
The patient, unable to recognize his or her own bite, becomes especially attentive to
these perceived oral discrepancies.
Finally and most recently, Greene and Gelb suggested that instead of having a psychological
root, dysesthesia may be caused by a false signal being sent from the peripheral nervous
system to the central nervous system.
However, the reviewers note that no method exists for determining sensor nerve thresholds,
and so sensory perception in the mouth is often measured by interdental thickness discrimination,
or the ability to differentiate between the sizes of objects placed between teeth.
In one study, occlusal dysesthesia patients showed greater ability to differentiate these
thicknesses than control, healthy individuals, but these differences were not statistically
significant.
Studies Bennett et al. produced an artificial peripheral
mononeuropathy in rats by surgically constricting the sciatic nerve.
These rats showed an increased response to noxious radiant heat, were nocifensive when
placed on a cold metal floor, protected their hind paws, and had suppressed appetite.
Additionally, the paws of many of these rats were inappropriately warm or cool to the touch,
and many of the rats overgrew claws on the affected paws as well.
These results indicate that the rats exhibited hyperalgesia, allodynia, and dysesthesia.
In a study in which researchers cut spinal nerves in rats, researchers found these rats
exhibited a longer duration in spontaneous foot lifting, hypersensitivity to mechanical
stimuli, allodynia, and hyperalgesia.
Additionally, the receptive field neurons in this nerve pathway showed spontaneous firing
in low-threshold nociceptors, suggesting that nerve damage can cause dysesthesia.
In women suffering from chronic pain or itchy scalps without any apparent physical cause,
about half were suffering from psychiatric disorders.
For the majority of these women, their symptoms of scalp dysesthesia were alleviated or removed
by treatment with low doses of antidepressants.
Landerholm et al. hypothesized that dynamic mechanical allodynia might be the hyperbole
of dynamic mechanical dysesthesia, mediated by peripheral nerves.
When the researchers artificially blocked nerves in patients suffering from peripheral
neuropthic pain or central post-stroke pain, DMA symptoms in many of the patients transitioned
into DMD symptoms.
Additionally, the researchers determined that the number of mechanocreceptive fibers associated
with the nociceptive system was responsible for the differentiation of DMA to DMD.
Ochoa et al. recorded intraneural signals in subjects with post-ischaemic paraesthesiae.
The researchers found the signals to be spontaneous.
The frequency of the signals paralleled the intensity and timing of the paresthetic sensations
reported by the patients.
These results suggest that paresthetic sensations are the result of inappropriate firing frequency
and timing by impulses from sensory cells.
Tuskiyama et al. assessed occlusal dysesthesia patients using an interdental thickness discrimination
test and a psychological examination.
The researchers found that occlusal dysesthesia patients could not discriminate the thickness
of material in their bite any better than normal dental patients, but that the occlusal
dysesthesia patients were significantly more likely to exhibit psychological disorders.
Living with dysesthesia A patient suffering from dysesthesia can find
it to be unbearable at times.
Dysesthetic burning has been called "Dante-esque" pain.
The terminology used to describe it is usually interchangeable with descriptions of Hell
in classic literature.
It is the "bluntest" pain of which the human body is capable, and is characterized by the
absence of accurate discriminative information.
Temperature change and heat both affect the sensation and raise the level of the steady
pain.
This pain upgrades with tonic light touch, phasic rubbing, or rough textures to become
evoked pain.
The patient often cannot endure the touch of clothing.
His or her entire life becomes an exercise in avoiding evoked pain.
It causes difficulty in obtaining rest because bed-clothing contacts the skin.
It drives the patient to a hysterical search for relief of the pain, which ends in some
degree of resignation and frequent depression.
Patients indicate that it has robbed them of their identity, since their values and
mental priorities are so consumed by its avoidance.
Chronic anxiety is often associated with dysesthesia.
Patients suffering from this anxiety may experience numbness or tingling in the face.
In one study, those patients that were examined psychologically had symptoms of anxiety, depression,
obsessive-compulsive personality disorder, or somatoform disorder.
Treatment Daily oral muscle physical therapy, or the
administration of antidepressants have been reported as effective therapy for occlusal
dysesthesia patients.
Tooth grinding, and the replacement or removal of all dental work should be avoided in patients
with occlusal dysesthesia, despite the frequent requests for further surgery often requested
by these patients.
Antidepressants are also often prescribed for scalp dysesthesia.
Prakash et al. found that many patients suffering from burning mouth syndrome, one variant of
occlusal dysesthesia, also report painful sensations in other parts of the body.
Many of the patients suffering from BMS met the cclassification of restless leg syndrome.
About half of these patients also had a family history of RLS.
These results suggest that some BMS symptoms may be caused by the same pathway as RLS in
some patients, indicating that dopaminergic drugs regularly used to treat RLS may be effective
in treating BMS as well.
See also Paresthesia
Scalp dysesthesia References
Further reading External links
Chiari & Syringomyelia Foundation