Hyperhidrosis is a condition characterized by excessive sweating of the hands, which are wet and cold. There are two categories, primary and secondary. Primary hand sweating is excessive sweating of the hands not caused by other diseases or medications, which is the most common; secondary is sweating caused by hyperthyroidism, tuberculosis and other diseases, which is less common. When combined with excessive sweating of the feet, it is called hyperhidrosis of the hands and feet. The prevalence of hyperhidrosis is about 3%; there is no gender difference, and it often begins in childhood or adolescence. The cause of primary hand sweating is not known and there is a genetic predisposition. How does hand sweating occur? There is a pair of thoracic sympathetic nerves in the human thoracic cavity, which control the secretion of sweat glands in the hands and feet, and due to its overexcitation, it leads to increased sweating in the hands and feet. The initial diagnosis can be made on the basis of the symptoms, which are relatively easy and do not require special tests. Only moderately severe cases of hand sweating need to be treated. Regarding the grading of severity: Mild: moist palms; Moderate: sweaty palms soaked through a tissue paper; Severe: sweaty palms in the form of water droplets.