Ichthyosis Ichthyosis Ichthyosis is a family of rare genetic skin disorders characterized by dry, thickened, scaly skin. There are more than 20 types of ichthyosis which range in severity of symptoms, outward appearance, underlying genetic cause and mode of inheritance (e.g., whether the abnormal gene inherited is dominant, recessive, autosomal or X-linked). Ichthyosis comes from the Greek ἰχθύς, ichthys, literally "fish", since dry, scaly skin is the defining feature of all forms of ichthyosis. The severity of symptoms can vary enormously, from the mildest, most common, types such as ichthyosis vulgaris, which may be mistaken for normal dry skin, up to
Heterogeneous condition case, in which it is not possible to speak about a single disease associated to the clinical course of the patient. While the term "medical condition" generally includes mental illnesses, in some contexts the term is used specifically to denote any illness, injury, or disease except for mental illnesses. The Diagnostic and Statistical Manual of Mental Disorders (DSM), the widely used psychiatric manual that defines all mental disorders, uses the term "general medical condition" to refer to all diseases, illnesses, and injuries except for mental disorders. This usage is also commonly seen in the psychiatric literature. Some health insurance policies