Increased skin temperature is commonly associated with erythermalgia. Erythromelalgia is a disorder caused by excessive vasodilation of the extremities and is characterized by paroxysmal redness, increased skin temperature and burning pain in a warm environment. Primary cases are more common. It is a rare disease. Patients are mostly children or 40 years old. It is reported that there are more male patients than female patients, about 2/1. However, among the 433 cases reported in Guangzhou, the largest number of young women, accounting for 92.86%, and the ratio of male to female is 1/13. I. Symptom examination: The onset of the disease is rapid, often in a warm environment when the limb drops, stands or moves, causing an attack or aggravating the attack. Local skin temperature exceeding the critical temperature often causes seizures, and nighttime seizures are often heavier than daytime. The attack is characterized by symmetrical, paroxysmal, severe pain in both feet, mostly burning pain, occasionally stabbing pain or swelling pain. The skin is flushed and congested, and the skin temperature is increased with sweating. The dorsalis pedis and posterior tibial artery pulsations are increased. Cold compresses, elevation of the affected limb or exposing the foot to the outside of the bed, and local temperature below the critical temperature may relieve the attack and restore the skin color to normal. The pain is usually confined to the bunions and toes of the foot and, less commonly, to the corresponding areas of the hand. Each attack lasts for several minutes or even hours and is occasionally accompanied by local edema. Between attacks, the extremity is often left with mild numbness or pain, but is not accompanied by neurotrophic disorders such as ulceration or gangrene. Second, the instrument examination: 1, the skin critical temperature test: the foot or hand immersed in 32 ~ 36 ℃ water, if the symptoms appear or symptoms aggravated that is positive. 2, nail wrinkle microcirculation examination shows that the capillary collaterals are blurred and dilated, and the pressure inside them is increased, which is more serious after giving thermal stimulation. 3.Blood routine, urine routine, blood biochemical examination. 4.Vascular ultrasonography.