What characterizes pustules?

Pustules are characterized as pus-filled sacs that form on the surface of the skin. This definition is crucial in differentiating pustules from other skin lesions. They typically present as swollen, inflamed areas that contain white or yellowish fluids, which is indicative of an infection or inflammation. Pustules often occur in conditions such as acne or folliculitis, where the skin's oil glands and hair follicles become clogged and subsequently inflamed.

Understanding that pustules are specifically filled with pus helps clarify why they have a distinct appearance and why they signify particular skin issues. Other choices describe different types of skin lesions: small black spots refer to comedones, raised red boils suggest abscesses or cysts, and dry, scaly patches indicate conditions like psoriasis or eczema. Thus, recognizing the unique fluid-filled nature of pustules is essential in dermatological assessments and treatments.