Which condition is described as skin becoming extremely dry and scaly?

The condition characterized by the skin becoming extremely dry and scaly is ichthyosis. Ichthyosis is a genetic skin disorder that leads to the excessive production of skin cells, resulting in dry, thickened, and often scaly skin. The name itself is derived from the Greek word "ichthys," meaning fish, which alludes to the fish-like appearance of the skin.

Ichthyosis can manifest in several forms, ranging from mild to severe, and it often requires ongoing management to keep the skin moisturized and to reduce scaling. This condition is distinct in its nature, as it primarily revolves around the abnormal keratinization process in the skin, leading to a thickened outer layer.

Other conditions like atopic dermatitis and psoriasis do involve dry or flaky skin, but they also include other symptoms such as itching, inflammation, and redness. Hyperhidrosis, on the other hand, pertains to excessive sweating and is not associated with dryness or scaling. Therefore, the unique characteristics of ichthyosis clearly define it as the condition specifically linked to extreme dryness and scaliness of the skin.