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. The ratio of male to female is about 2/1. However, among the 433 cases reported in Guangzhou, young women are the most common, accounting for 92.86%, and the ratio of male to female is 1/13. The following diseases may also cause increased skin temperature: 1. Lupus erythematosus Lupus erythematosus (LE) is a typical autoimmune connective tissue disease, mostly seen in women aged 15 to 40. Lupus erythematosus is a disease spectrum disease and can be divided into subtypes such as discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), systemic lupus erythematosus (SLE), profound lupus erythematosus (LEP), neonatal lupus erythematosus (NLE), and drug-induced lupus erythematosus (DIL). 2. Cardiomyopathy Cardiomyopathy is a progressive disorder of heart function due to structural changes in the lower chambers of the heart and impaired function of the heart muscle wall. Cardiomyopathy can lead to gradual weakening of the heart, irregular heart rhythm and eventually heart failure, but the coronary arteries are mostly normal. People of any age have the opportunity to develop this disease. Alcoholism refers to the mental and physical disorders caused by alcohol consumption. Alcoholic dependence refers to a series of withdrawal symptoms that can occur once a chronic alcoholic stops drinking. In fact, alcoholic dependence is often in a state of intoxication. The incidence of alcoholism in China is lower than that in western countries, but in recent years its incidence seems to have a tendency to increase and should be taken seriously. 4, true erythrocytosis True erythrocytosis (PV) is a clonal disease of hematopoietic stem cells of unknown cause, belongs to the category of myeloproliferative diseases. It is characterized by a significant increase in the number and volume of red blood cells, manifestations of polycythemia and hyperviscosity, and is often accompanied by splenomegaly. The skin and mucous membranes are markedly red and purple, especially the cheeks, lips, tongue, ears, tip of the nose, neck and the ends of the extremities (fingers and toes and greater pelvic area). The ocular conjunctiva is significantly congested. About 2/3 of patients often have hepatomegaly, which is mostly mild. Later stages can lead to cirrhosis, called Mosse’s syndrome. Patients mostly have splenomegaly, mostly more pronounced, and splenic infarction may occur, causing peripleural inflammation. 5, thrombo-occlusive vasculitis Thrombo-occlusive vasculitis is a rare chronic recurrent segmental inflammatory disease of the small and medium-sized arteries and veins, mostly in the lower extremities. It is characterized by ischemia, pain, intermittent claudication, diminished or absent dorsalis pedis artery pulsation and wandering superficial phlebitis in the affected limbs, and ulceration and necrosis in the severe cases. 6, hypertension hypertension (hypertensive disease) is a chronic disease with a sustained increase in arterial blood pressure as the main manifestation, often causing lesions of the heart, brain, kidneys and other important organs and the corresponding consequences.