Which description best defines a vesicle?

• A. A circumscribed, elevated solid lesion up to 1 cm
• B. A circumscribed, elevated fluid-filled lesion larger than 1 cm
• C. A flat pigmented spot
• D. A circumscribed, elevated lesion containing clear fluid less than 1 cm

Answer: (D)

Vesicles are small, fluid-filled, raised skin lesions. The key features are that they are circumscribed and elevated, contain clear fluid (serous fluid), and are less than 1 cm in diameter. This combination distinguishes them from other lesions: if the fluid is pus, it’s a pustule; if the fluid-filled lesion is larger than 1 cm, it’s a bulla; a solid elevated lesion is a papule or nodule; a flat pigmented spot is a macule. Therefore, the description of a circumscribed, elevated lesion containing clear fluid and measuring under 1 cm fits a vesicle.