Ichthyosis is an inherited skin condition that causes thick, dry scales to appear on the surface of the skin. The scales form when skin cells and proteins begin to build up in the outer layer of skin (a result of the skin’s natural shedding process slowing down or being inhibited in some way). Ichthyosis is often caused by a genetic mutation and it can be present and visible at birth, but it can also appear during early childhood. Common side effects include pain and severely dry, flaky skin. Most cases are mild and can be treated with topical medication. In more severe cases, retinoid medicine may be used.