What type of skin lesions appear as small, fluid-filled sacs?

The correct answer is vesicles, which are defined as small, fluid-filled sacs that form within the skin. Vesicles are typically less than 1 centimeter in diameter and can appear in clusters. They are often associated with conditions such as herpes simplex, chickenpox, or contact dermatitis. Due to their fluid content, vesicles can rupture, leading to the formation of weeping lesions.

In contrast, macules are flat and pigmented spots on the skin that do not have a raised texture and do not contain fluid. Papules are small, raised bumps that are solid and may also be inflamed, but they do not contain liquid. Crusts are formed when dried bodily fluids, such as serum or pus, accumulate on the skin surface after lesions weep or ulcerate. Understanding these distinctions is essential for accurately identifying and treating various skin conditions.