DefinitionThis section has been translated automatically.
In medicine, allodynia (gr. allos "different"; odyne "pain") is a pain sensation that is triggered by stimuli that normally do not cause pain.
ClassificationThis section has been translated automatically.
Dynamic-mechanical allodynia: Slightly moving skin stimuli, e.g. cotton balls, trigger pain. Location: In the primary zone of the disease, spreading partly far into uninjured skin areas (secondary zone).
Punctiform allodynia: Normally slightly stinging but not painful stimuli (stiff von Frey hair) trigger pain. Location: In the primary zone of injury and spreading partly far into uninjured skin areas (secondary zone).
Cold allodynia: Light cold stimuli trigger pain. Typical in traumatic nerve lesion and some polyneuropathies.
Heat allodynia: Mild warmth stimuli trigger pain. Typical in traumatic nerve lesion and some polyneuropathies.
Allodynia by summation: Repeatedly applied identical noxic stimuli are perceived as a steadily increasing pain sensation.
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EtiopathogenesisThis section has been translated automatically.
The pathogenesis of allodynia has not yet been fully clarified. It is conceivable that the stimulus may be redirected via low-threshold, normally non-nociceptive Aß touch afferences. Two different mechanisms are conceivable here:
- Central changes in the functionally effective synaptic structures so that impulses from Aß fibres in the spinal cord are switched to overexcited secondary nociceptive neurons (central sensitisation),
- Anatomical connection of Aß-fibres in the spinal cord to secondary nociceptive neurons (anatomical reorganisation in the posterior horn)
The symptom of allodynia occurs in a variety of neurological diseases. A typical example is zoster infection. Other diseases:
- Neuropathies of other genesis
- postherpetic neuralgia
Differential diagnosisThis section has been translated automatically.
Allodynia must be distinguished from hyperalgesia, where an already painful stimulus triggers a more intense pain.
Note(s)This section has been translated automatically.
The pathogenetic analogue of allodynia is allocnesis/hyperknesis in the triggering of itching.
Outgoing links (1)Zoster;
Please ask your physician for a reliable diagnosis. This website is only meant as a reference.