erythromelalgia , rare disease in which the blood vessels of the hands and feet go through spasms of dilation associated with burning pain, increased skin temperature, and redness. The disease may be primary (in which case the cause is unknown), or secondary (caused by underlying disorders of the nervous system, blood, or vascular system). It may be exacerbated by external heat and exercise. Treatment includes rest, elevation of the extremity, and cold applications. Aspirin can be used to relieve pain.