The characteristic maculopapular rash of measles follows a predictable sequence of spread. In which order does the rash typically progress?

Explanation

## Sequence of Measles Rash Spread **Key Point:** The measles rash appears in a characteristic centrifugal (outward) pattern, beginning at the hairline and progressing downward and outward over 3–4 days. This predictable sequence is a hallmark of measles diagnosis. **High-Yield:** The rash typically appears on day 3–4 of illness, starting at the hairline and behind the ears, then spreading to the face, trunk, and finally the extremities. The rash becomes confluent on the face and trunk but remains discrete on the extremities. ## Timeline and Characteristics of Measles Rash | Day | Location | Appearance | Characteristics | |-----|----------|------------|------------------| | **Day 3–4** | Hairline, behind ears | Discrete macules/papules | Starts at hairline | | **Day 4–5** | Face, neck | Becomes confluent | Spares palms and soles | | **Day 5–6** | Trunk, upper extremities | Confluent on trunk, discrete on extremities | Blanching, non-pruritic | | **Day 6–7** | Lower extremities | Discrete macules/papules | Rash begins to fade | | **Day 7–10** | All areas | Desquamation may occur | Fading in same order | **Clinical Pearl:** The rash spares the palms and soles, which helps distinguish measles from other exanthems (e.g., Rocky Mountain spotted fever, which involves palms/soles; varicella, which is polymorphic). **Mnemonic:** **"Hair-Face-Trunk-Feet"** — Remember the centrifugal spread of measles rash from head to toe. [cite:Harrison 21e Ch 219]