While occasionally someone afflicted with Fibromyalgia is told he may have Reflex Sympathetic Dystrophy (RSD), it is not uncommon for someone with RSD to be told he has Fibromyalgia. Unfortunately, this only adds confusion to those with either of these disorders.

The hallmark of RSD is cold sensitivity in the presence of vasomotor and sudomotor change (abnormal skin color and sweating), which may progress to edema (swelling), contracture (loss of range of motion), and bone loss. Symptoms usually begin after an identifiable, causative event. In patients with RSD, the weather-sensitive component may manifest itself as pain that increases with barometric change. This is a noticeable worsening and a major feature in those with RSD.