Risk factors for serious pathology (also known as red flags)

Unexplained deformity or swelling or erythema of the skin; significant weakness not due to pain; past history of malignancy; suspected malignancy (e.g., weight loss or loss of appetite); fever/chills/malaise; significant unexplained sensory/motor deficits; pulmonary or vascular compromise; inability to perform any movements; pain at rest.