Which skin lesion is characterized by scales or shedding flakes of greasy, keratinized tissue?

The characteristic of scales or shedding flakes of greasy, keratinized tissue is most commonly associated with psoriasis. This skin condition is an autoimmune disorder that leads to the rapid proliferation of skin cells, resulting in thick, silvery-white scales appearing on the surface of the skin. These plaques often form due to an accelerated skin cell life cycle, leading to a buildup that becomes visible as flaky or scaly patches.

In psoriasis, the scales can vary from small dots to large plaques and are typically found on elbows, knees, scalp, and lower back. Unlike other conditions, psoriasis is not primarily characterized by inflammation alone; the distinctive flaky appearance is a key feature in identifying it.

In contrast, eczema is marked by dry, itchy, and inflamed skin rather than greasy scales, herpes involves blister-like lesions, and impetigo presents with crusted sores but is not associated with the characteristic scaling of psoriasis. Thus, the defining features of psoriasis make it the correct choice for the question about lesions with scales or shedding flakes.