Causalgia is persistent and extreme burning sensations,
usually in an arm or leg, accompanied by redness. These
sensations usually occur after partial injury to the brachial
plexus (a major nerve in the spine that goes to the arms)
or a peripheral sensory nerve (a nerve in the body
outside of the brain or spinal cord that provides
sensation). The peripheral sensory nerves typically
involved in causalgia are the median nerve (which goes
to the forearm) or the tibial nerve (which goes to the leg
and foot). The partial injury to the previously mentioned
nerves causes the nerve supply to be interrupted.
FEATURED BOOK: Pain Free: A Revolutionary Method for Stopping Chronic Pain

Allodynia can also occur in causalgia, which is a condition in which something that does
not ordinarily cause pain actually does cause pain. The symptoms of causalgia can
extend beyond the body area known to be supplied by the injured nerve. Other signs of
causalgia include edema (swelling), changes in skin blood flow, and abnormal sweating
activity in the region of the pain. Causalgia is painful and difficult to control but is treated
with different types of medications and physical therapies.

Causalgia is now more commonly referred to as Type II complex regional pain syndrome
(CRPS). Causalgia comes from the Greek word "kausis" meaning "burning," and the
Greek word "algos" meaning "pain." Put the two words together and you get "burning
pain." The term “causalgia” was coined by the English physician, Robley Dunglison.
"Where Medical Information is Easy to Understand"™