Eczema is an inflammatory skin reaction caused by a variety of internal and external factors that cause intense itching. There are three phases: acute, subacute, and chronic. The acute phase has a tendency to exude, while the chronic phase is infiltrative and hypertrophic. Some patients directly present with chronic eczema. The lesions are polymorphic, symmetrical, pruritic, and prone to recurrence. Eczema has a complex etiology, often as a result of the interaction of internal and external factors. Internal factors such as chronic digestive diseases, mental stress, insomnia, overexertion, emotional changes, endocrine disorders, infections, metabolic disorders, etc., and external factors such as living environment, climate change, food, etc., can affect the occurrence of eczema. External stimuli such as sunlight, cold, dryness, heat, hot water scalding and various animal fur, plants, cosmetics, soap, artificial fibers, etc. can induce. It is a delayed metabolic reaction caused by complex internal and external factors. According to TCM theory, in acute cases, damp-heat is the main cause; in subacute cases, it is mostly related to spleen deficiency and dampness; in chronic cases, the skin loses moistening and nourishment due to blood deficiency and dryness; or due to damp-heat blockage due to abnormal operation of qi and blood. For recurring eczema, a correct “forensic analysis” and a combination of internal and external treatment can be far more effective than simple Western medicine treatment.