Children’s skin long a grain, consider the following kinds of diseases: First, children’s papulopapular extremity dermatitis, this disease occurs in the limb area, can appear maculopapular rash, papules, is due to hepatitis B virus infection and other factors. Second, periosteal keratosis, this disease occurs in the upper arm extension, can appear follicle consistency papules, is due to genetic factors. Third, molluscum contagiosum, is due to the infection of human molluscum contagiosum virus and caused by the skin color round small papules, the top of the umbilical concave. Fourth, eczema, is due to allergic factors or infectious factors, internal disease factors. Fifth, psoriasis vulgaris, is due to polygenic inheritance and a variety of causes.