Severe<unk>  of right arm<unk>  visible on hands and wrists Clinical features of<unk>  have been found to be inflammation resulting from the release of certain proinflammatory chemical signals from the nerves, sensitized nerve receptors that send pain signals to the brain, dysfunction of the local blood vessels' ability to constrict and dilate appropriately, and maladaptive neuroplasticity. The signs and symptoms of<unk>  usually manifest near the injury site. The most common symptoms are extreme pain, including burning, stabbing, grinding, and throbbing. The pain is out of proportion to the severity of the initial injury. Moving or touching the limb is often intolerable. With diagnosis of either<unk>  types I or II, patients may develop burning pain and allodynia. Both syndromes are also characterized by autonomic dysfunction, which presents with localized temperature changes, cyanosis, and/or edema. The patient may also experience localized swelling; extreme sensitivity to nonpainful stimuli such as wind, water, noise, and vibrations; extreme sensitivity to touch (by themselves, other people, and even their clothing or bedding/blankets); abnormally increased sweating (or absent sweating); changes in skin temperature (alternating between sweaty and cold); changes in skin colouring (from white and mottled to bright red or reddish-violet); changes in skin texture (waxy, shiny, thin, tight skin); softening and thinning of bones; joint tenderness or stiffness; changes in nails and hair (delayed or increased growth, brittle nails/hair that easily break); muscle spasms; muscle loss (atrophy); tremors; dystonia; allodynia; hyperalgesia; and decreased/restricted ability and painful movement of affected body part. Drop attacks (falls), almost fainting, and fainting spells are infrequently reported, as are visual problems. The symptoms of<unk>  vary in severity and duration. Since<unk>  is a systemic problem, potentially any organ can be affected. Symptoms may change over time, and they can vary from person to person. Symptoms can even change numerous times in a single day. Previously,<unk>  was considered to have three stages however more recent studies suggest people affected by<unk>  do not progress through sequential stages and the staging system is no longer in wide use. Growing evidence instead points towards distinct sub-types of<unk> .
Complex regional pain syndrome
Thoracic outlet syndrome
Calpainopathy
Myofascial pain syndrome
Central pain syndrome
Nerve compression syndrome
Radiation-induced lumbar plexopathy
Polymyalgia rheumatica