Ichthyosis is a heterogeneous family of at least 28, generalized, mostly genetic

Genetic disorder

A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....

 skin

Skin

-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 disorders

Dermatology

Dermatology is the branch of medicine dealing with the skin and its diseases, a unique specialty with both medical and surgical aspects. A dermatologist takes care of diseases, in the widest sense, and some cosmetic problems of the skin, scalp, hair, and nails....

. All types of ichthyosis have dry, thickened, scaly or flaky skin. In many types there is cracked skin, which is said to resemble the scales on a fish; the word ichthyosis comes from the Ancient Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 ιχθύς (ichthys

Ichthys

Ichthys, from Koine Greek: , is the Greek word for "fish"....

), meaning "fish." The severity of symptoms can vary enormously, from the mildest types such as ichthyosis vulgaris

Ichthyosis vulgaris

Ichthyosis vulgaris is a skin disorder causing dry, scaly skin. It is the most common form of ichthyosis, affecting around 1 in 250 people. For this reason it is known as common ichthyosis...

 which may be mistaken for normal dry skin up to life-threatening conditions such as harlequin type ichthyosis

Harlequin type ichthyosis

Harlequin-type ichthyosis , a skin disease, is the most severe form of congenital ichthyosis, characterized by a thickening of the keratin layer in fetal human skin...

.