Which disease features lesions that have a depression in the center and are all at the same stage, spreading from the face/arms to trunk/legs?

Which disease features lesions that have a depression in the center and are all at the same stage, spreading from the face/arms to trunk/legs?

• A. Measles
• B. Rubella
• C. Varicella
• D. Smallpox

Answer: (D)

The key idea is the pattern of the rash in smallpox: the lesions are all at the same stage at once (synchronous) and the eruption spreads outward from the face and extremities toward the trunk and legs (centrifugal spread). Each lesion tends to be deep-seated and often has a central depression, or umbilication. This combination—uniform lesion stage, central hollowing, and a face-to-extremities spread—is classic for smallpox and helps distinguish it from other exanthems. Measles and rubella produce maculopapular rashes that typically spread head to toe but lack vesicular lesions with a central depression and don’t present with all lesions in the same stage. Varicella shows crops of vesicles at different stages (some new papules, some vesicles, some crusts) and tends to be more trunk-centered, lacking the uniform, deeply seated lesions with central pits seen in smallpox.

The key idea is the pattern of the rash in smallpox: the lesions are all at the same stage at once (synchronous) and the eruption spreads outward from the face and extremities toward the trunk and legs (centrifugal spread). Each lesion tends to be deep-seated and often has a central depression, or umbilication. This combination—uniform lesion stage, central hollowing, and a face-to-extremities spread—is classic for smallpox and helps distinguish it from other exanthems.

Measles and rubella produce maculopapular rashes that typically spread head to toe but lack vesicular lesions with a central depression and don’t present with all lesions in the same stage. Varicella shows crops of vesicles at different stages (some new papules, some vesicles, some crusts) and tends to be more trunk-centered, lacking the uniform, deeply seated lesions with central pits seen in smallpox.