Psoriasis of the head is a skin disorder mediated by a combination of environmental and genetic factors. Seborrheic dermatitis of the head generally develops as a result of a fungal infection of the scalp. The difference between the two mainly lies in the different pathogenesis and clinical manifestations. 1. Pathogenesis: the pathogenesis of head psoriasis is not very clear, may be due to genetic factors, environmental factors and immune factors jointly mediated by a kind of skin disease; head seborrheic dermatitis is due to the scalp oil secretion, at the same time concurrently with Malassezia infection of the formation of scalp inflammation. 2. Clinical manifestations: seborrheic dermatitis of the scalp is usually manifested as greasy scales on the basis of erythema, or dry white fine flakes, and the border is usually unclear; psoriasis of the head is usually manifested as nail-sized or dotted-drop red macules, and the surface of lesions can be seen as layers of accumulation of fat white scales, and the hair can be bundled. Whether the patient’s head is seborrheic dermatitis or psoriasis, it is recommended that the patient go to the hospital in time for examination, to clarify the cause of the disease under the guidance of the doctor for symptomatic treatment.