The difference between eczema and solar dermatitis lies in the different causes, rash symptoms, and sites of onset. 1. Pathogenesis: eczema is caused by a variety of internal and external factors in the superficial dermis and epidermal inflammation, such as chronic infection foci, endocrine and metabolic changes, neuropsychiatric factors, genetic factors, such as food, inhalants, the living environment, animal fur, a variety of chemicals or aggravation of the triggering. Solar dermatitis is due to strong sunlight exposure, sun exposure occurs in the skin of acute phototoxic reaction. 2. Rash pattern: eczema rash shape is diverse, mostly manifested as symmetrical body erythema, papules, flaking, especially in the acute stage of eczema, there will be vesicles oozing. Solar dermatitis is a large erythema, erythema border is clear, on which can be seen papules, papules, blisters and other manifestations, rarely appear vesicles oozing. 3. Onset site: eczema can occur in any part of the body, while solar dermatitis is only seen in the area of sun exposure. Regardless of the disease, it is recommended to go to the hospital in a timely manner, by a professional doctor to clarify the diagnosis, symptomatic treatment.