Erythrodermic limb pain is a peripheral vasodilatory dysfunctional disease characterized clinically by redness, swelling, pain and heat in the skin of the extremities, mostly in both feet, with associated symptoms such as moaning, severe pain, sensory hypersensitivity, heat pain, preference for cold and fear of heat. The disease is mostly seen in young adults aged 20 to 40 years old, with more males than females. Clinical manifestations include palpitations, spontaneous sweating, increased appetite with weight loss, emotional irritability, hand tremors, protruding eyes and goiter. Causes: The cause of erythema extremities may be related to the capillary diastolic dysfunction at the extremities due to cold. Due to the dilation of small arteries in the extremities, blood flow increases significantly, local congestion, and increased intravascular tension, which compresses or stimulates the arteries and adjacent nerve endings and produces severe pain. It is often triggered by sudden drop in temperature and cold or long-distance marching. There are three types: 1. Primary erythema limb pain may be related to autonomic or vascular nerve center dysfunction, skin hypersensitivity to temperature and increase in certain thermogenic substances in blood, and a few patients have family factors. 2.Secondary erythematous limb pain secondary to certain diseases, such as diabetes, true erythrocytosis, pernicious anemia, gout, mild cellulitis, rheumatoid arthritis, systemic lupus erythematosus, thrombo-occlusive vasculitis, carbon monoxide poisoning, heart failure, hypertension, etc. 3.Idiopathic erythema limb pain The causative factors of this disease may not be single, but the result of the combined action of many factors. First of all, it is related to the sudden change of temperature and cold stimulation. The fact that adolescent students are prone to this disease indicates that the autonomic and endocrine systems are unstable during adolescent development and have a poor ability to adapt to changes in the external environment, and whether it is related to certain biological pathogenic factors or nutritional deficiencies is uncertain.