There are many different types of ichthyosis, some of them are syndromic ichthyosis, in which in addition to the ichthyosquamous scales on the skin, there may be combined damage to internal organs or nervous system, such as spastic paraplegia of limbs, mental retardation and other manifestations. Doctors can use the patient’s skin manifestation to speculate whether he will combine with other system damage, and early diagnosis can control mental retardation and seizure at an early stage and improve the prognosis; some ichthyosis can combine with keratitis and deafness, so early detection and early intervention are very helpful; through the skin manifestation, we can further check whether the patient’s internal organ system may have abnormalities, so it is very necessary to let professional dermatologists Therefore, it is necessary to have a professional dermatologist make the diagnosis. Based on the patient’s subjective description and dermatological physical examination, we can determine whether it is ichthyosis, but for specific typing, we may need to do some special tests, such as pathological examination, histochemical examination, or even electron microscopy or finally genetic diagnosis for typing. The pathological examination is relatively routine, and if the patient has some special type of ichthyosis, there will be some special manifestations on the corresponding skin pathology. The patient will need to have a very small piece of skin stained and the cytologic changes looked at microscopically. Some cytologic changes can suggest a very precise staging, such as congenital herpetic ichthyosis which can be better diagnosed by skin pathology. Early determination of typing is very important for prognostic determination. For example, in syndromic ichthyosis, the skin manifestations can predict whether the patient will develop eye symptoms or deafness to decide whether to intervene earlier; in addition, the disease typing can also determine whether the patient will later develop a very severe ichthyosis or will gradually improve, which is very helpful for early medication selection. For example, in lamellar ichthyosis, patients may develop eyelid ectropion, corneal damage or finger contracture in adulthood, and if the disease is diagnosed early, it should be treated actively in childhood. The child may be given oral retinoids, which have potential side effects when used orally (usually as topical medication), but if the prognosis for such children is judged to be poor, early intervention and aggressive medication is required to avoid the complications mentioned above. Overall, it is important to judge the typing to determine the prognosis and guide the treatment.