In Complex Regional Pain Syndrome, CRPS (see below*), damage to the sympathetic vasoconstrictive function which affects blood vessels, can lead to localised hyperthermia (raised temperature).

This can lead on to hyperthermia in referred pain areas in other words, to more generalised raised temperature.

Note that opiate medication (morphine and related drugs) can cause facial flushing, as can antidepressants such as amitriptyline.

It is difficult to satisfactorily explain the highly common experience of wildly fluctuating body temperature that arachnoiditis sufferers undergo. Many people describe swinging from ?freezing' to ?boiling' within minutes and then back again.

The likelihood is that this relates to abnormal autonomic function, and is similar to the fluctuations in blood pressure mentioned below.

*Arachnoiditis may be considered a type of CRPS Type II. Type I is also known as Reflex Sympathetic Dystrophy, and is a localised version usually affecting one limb extremity.

Both types are characterised by:

• severe burning pain spontaneous and disproportionate to the trigger event; continuous and made worse by movement and touch,
• allodynia/hyperaesthesia, localised swelling which may cause nerve compression which is similar to and can be confused with carpal tunnel (at the wrist)
• or tarsal tunnel (foot) syndrome or indeed,
• thoracic outlet syndrome, which affects the whole arm and hand (pain, pins and needles, weakness, numbness);
• sweating/absence of sweating , changes in skin colour/ temperature
• (later stages affect skin tone): initially warm, red and dry, later cyanotic (bluish), cold and sweaty, l
• ater still, in Stage III, it may be cool, glossy, pale or bluish.
• This is due to neurogenic inflammation. 
• Then there may be: hair growth changes,
• muscle spasms,
• dystonia (abnormal muscle tone)
• and tremor. 
• Later stages: loss of bone density may occur (Sudek's Atrophy),
•  joint tenderness and swelling; causing reduced mobility;
• Skin rashes (including neurodermatitis)
• and nodules.
• The affected part may not feel 'part of the body any longer', leading to a tendency to 'neglect' (inattention to) this affected part therefore the patient may drop objects if hand affected or trip over if foot affected.
  

Type II CRPS also involves development of secondary problems such as headaches and later stages may involve myoclonic jerks as well as atonic falling attacks; bouts of unexplained fever,  Interstitial cystitis