Lymphadenitis is often referred to as lymphadenitis and can be categorized as acute lymphadenitis, chronic lymphadenitis, and atopic lymphadenitis. The main pathogens that cause lymphadenitis are bacteria, viruses and Mycobacterium tuberculosis. Infants, young children and immunocompromised people are the most common groups of lymphadenitis. 1. Acute lymphadenitis: Inflammation of organs or tissues around lymph nodes, such as colds, rhinitis, etc., will cause acute enlargement of nearby lymph nodes, resulting in acute lymphadenitis, which is characterized by enlarged lymph nodes, pain, high skin temperature and tenderness. 2. Chronic lymphadenitis: often caused by persistent or repeated stimulation of pathogens, typically characterized by enlarged lymph nodes, tenderness and pain, and requiring a longer period of treatment. 3. Specific lymphadenitis: lymphadenitis caused by specific pathogens, such as Mycobacterium tuberculosis, requires specific drug treatment.