Eczema is an allergic disease caused by a variety of internal and external factors, because the pathogenesis is complex, uncontrollable factors, so it is easy to repeat, the following five common causes: 1, the persistence of causative factors: the pathogenesis of eczema is not completely clear, can be broadly divided into internal and external factors. Endogenous factors include chronic infection foci (chronic cholecystitis, etc.), blood circulation disorders (such as varicose veins in the lower extremities leading to bruising dermatitis), endocrine disorders, mental factors (neurodermatitis), genetic related, etc.; exogenous factors include diet (such as fish, shrimp, crab, beef and mutton, alcohol, etc.), living environment (formaldehyde, dust, household dust mites, pollen), etc.; if the causative factors cannot be clearly identified or cannot be avoided, the etiology persists and is easily repeated. 2.Repeated itching stimulates the skin, and the epidermis breaks down after the secondary bacterial infection, resulting in a prolonged course of the disease. 3, spicy and stimulating diet, poor living caused by decreased resistance. 4, irregular treatment, did not get effective treatment. 5, improper care: hot water scalding, do not apply emollient cream, resulting in the destruction of the skin barrier, prone to re-occurrence. Eczema is a large group of diseases that differ greatly depending on the specific condition, and the cause may be related to infection, immunity, diet, and care. If you have recurring eczema, you need to find a specialist, make a clear diagnosis, actively search for and remove as many triggers as possible, and collaborate on treatment and prevention to avoid recurring and prolonged attacks.