Which of the following is characteristic of psoriasis?

Psoriasis is an autoimmune condition that primarily affects the skin, resulting in specific visible symptoms. The hallmark characteristic of psoriasis is the presence of red patches covered with silvery-white scales. These patches often appear raised and can be itchy or painful. The scaling is due to an accelerated skin cell turnover, which leads to the accumulation of dead skin cells on the surface of the skin.

The red color of the patches is indicative of inflammation, while the silvery scaling results from the thickening of the stratum corneum, the outermost layer of the skin, as new cells are produced at an increased rate. This combination of red patches and silvery scales is distinctive enough to differentiate psoriasis from other skin conditions.

In contrast, conditions characterized by fluid-filled blisters, yellow crusted lesions, or multiple bruising spots represent different pathological processes and do not align with the defining features of psoriasis. For example, fluid-filled blisters may indicate conditions like dermatitis or herpes, while yellow crusted lesions could suggest an infection like impetigo, and multiple bruising spots may be a sign of vascular issues or trauma. Thus, the specificity of red patches with silver scaling is a defining feature of psoriasis.