The etiology of eczema is quite complex and is often the result of the interaction of multiple internal and external factors. External factors such as living environment and climatic conditions can affect the occurrence of eczema. External stimuli such as sunlight, ultraviolet light, daily necessities, certain foods, etc. can trigger eczema. Intrinsic factors such as chronic digestive diseases, mental stress, emotional changes, infectious lesions, metabolic disorders, etc. can produce or aggravate eczema. The pathogenesis of eczema is currently considered by most scholars to be a delayed metabolic reaction caused mainly by internal and external excitatory factors. Patients may have certain qualities that are governed by genetic factors.