The skin of a four-year-old baby should not be rough by definition, but if roughness occurs, there are two general conditions that may occur. The first condition may be congenital ichthyosis, because ichthyosis can be caused by dry and rough skin at an early age, mainly due to abnormal skin keratinization and keratinization of skin follicles, similar to chicken skin. In addition, there may be chronic eczema that causes rough skin. As the baby may have had eczema symptoms before this, but due to the lack of timely treatment, or the ineffectiveness of the treatment caused by this prolonged symptoms, the symptoms of dry, rough skin.