Danemia (erysipelas) is an infection that involves the superficial lymphatic vessels of the dermis, and the main causative agent is group A beta-hemolytic streptococcus. Predisposing factors are surgical wounds or fissures in the nostrils, external ear canal, under the earlobe, anus, penis and between the toes. Any inflammation of the skin, especially with chafing or ulceration provides a pathway for the causative organism to invade. Mild abrasions or scratching, injuries outside the head, unclean cord ligation, vaccinations, and chronic calf ulcers may cause the disease. The causative organism can be latent in the lymphatic vessels and cause recurrence. The disease is caused by the invasion of group A B hemolytic streptococcus, and its triggering factors are mainly skin or mucous membrane abrasions or other minor trauma, can also be caused by bloodstream infection, often secondary to rhinitis, oral mucosa and dental infection lesions, tinea pedis, calf ulcers, pruritic skin disease, inoculation, radioactive injury and skin chaps or minor friction, scratching and minor trauma can be induced, especially unclean wounds Some wounds can be so small that they are not easily detected, such as facial dermatitis, which can be caused by a small wound in the nasal cavity that is scratched. 2, lower immune function This disease occurs when the body’s immune function is reduced, systemic diseases such as diabetes, chronic nephritis, hypogammaglobulinemia and alcoholism can become the cause of the disease, infants such as the occurrence of dermatitis can lead to sepsis, the mortality rate is high. Other factors such as malnutrition, excessive alcoholism, gammaglobulin deficiency and nephrogenic edema can all be contributing factors to the development of dysentery. Common symptoms: chills, fever, headache, nausea, vomiting, rapid onset, local redness and swelling, clear boundaries, high fever and pain with an incubation period of 2-5 days. The prodromal symptoms include sudden onset of fever, chills, malaise and nausea. Erythema appears a few hours to a day later and expands progressively with clear boundaries. The affected area is dermatologically warm and tense with hard nodules and non-depressed edema. Tenderness and burning pain are present in the involved area, and enlarged proximal lymph nodes with or without lymphadenitis are common. Pustules, blisters, or small areas of hemorrhagic necrosis may also be present. It is more common on the lower legs and face. Recurrence of denudation can cause persistent local lymphedema with the end result being permanent hypertrophic fibrosis called chronic streptococcal lymphedema. Breast cancer patients with axillary lymph node dissection are also prone to recurrence of dermatophytosis due to lymphatic stagnation. Routine blood test, histopathological examination of swab gram stain and bacterial culture of wounds and breaks; blood anti-chain and blood leukocytes; fungal examination of dander between toes should be performed for lower limbs; radiological examination of paranasal sinuses should be performed for facial dander. Fourth, prevention should actively look for skin lesions that can lead to the entry of pathogenic bacteria such as scratching, breakage or trauma of eczema, and once these skin lesions are found, they should be actively treated. The most common, easily overlooked and untreated susceptibility factor is tinea pedis, which can be a gateway for bacteria to enter the skin. Patients should be instructed not to pick their nose.