What is a typical characteristic of pustules?

Pustules are typically characterized by their raised structure and the presence of pus within them. This formation occurs when an accumulation of white blood cells, bacteria, and other cellular debris collect in a small area beneath the skin, leading to a swollen appearance that is often red and inflamed. The pus, which is usually yellow or white, gives pustules their distinct look and differentiates them from other types of lesions.

While some other options touch on characteristics of skin conditions, they do not accurately describe pustules. For example, the descriptions of being colorless or flat and painless do not align with the conventional understanding of pustules, which are known for being elevated, often painful, and visibly filled with yellowish fluid. Additionally, referring to pustules simply as blemishes does not capture their specific nature as pus-filled lesions. Thus, the defining feature of being raised and filled with pus accurately identifies what a pustule is.