What is a characteristic feature of ichthyosis?

Ichthyosis is characterized by thickened, dry skin that often appears scaly, resembling the scales of fish, which is actually where the name comes from, as "ichthyos" is Greek for fish. This condition results from a defect in the skin's ability to shed dead cells, leading to a buildup that creates a rough texture. The skin may appear red and inflamed underneath the scales, but the most distinctive feature is indeed the fish-scale appearance, making it easily identifiable.

Other attributes associated with ichthyosis can include varying degrees of dryness and other symptoms but they do not define the condition as strongly as the characteristic scaling. For instance, while warm, moist skin and excessive sweating reflect skin conditions like hyperhidrosis or eczema, these are not features of ichthyosis. Similarly, dark pigmented spots are more commonly associated with other dermatological conditions rather than with ichthyosis. Thus, the defining characteristic of ichthyosis is the thicker skin with a fish scale appearance.