According to the International Association for the Study of Pain, four characteristic features are required for the diagnosis of RSD / CRPS:
- the presence of a precipitating event or a cause of immobilization;
- continuous pain that is disproportionate to the precipitating injury. This may consist of pain from an innocuous stimulus or from an overly painful response to a minimal stimulus;
- evidence of edema (swelling of a limb), changes in skin blood flow in the region of pain, or sub-motor activity;
- exclusion of any other underlying medical condition that could cause the level of pain or dysfunction being experienced by the patient.
Not all medical doctors have accepted the International Association for the Study of Pain’s diagnostic criteria as there is no consensus at this time as to how many signs or symptoms must be present for an accurate diagnosis of RSD / CRPS. Therefore, any combination of the aforementioned signs and symptoms may result in a differential diagnosis of RSD / CRPS.