What is the characteristic sequence of spread of the measles rash across the body?

Explanation

## Measles Rash: Cephalocaudal Spread Pattern **Key Point:** The measles exanthem follows a characteristic **cephalocaudal** (head-to-toe) progression, starting on the face and hairline, then spreading to the trunk, and finally to the extremities over 3–4 days. ### Timeline and Distribution | Day of Illness | Location | Characteristics | |---|---|---| | **Day 3–4** | Face, hairline, behind ears | Maculopapular, blanching initially | | **Day 4–5** | Trunk (spreads downward) | Becomes confluent; may become non-blanching | | **Day 5–6** | Extremities (arms, legs, palms, soles) | Rash reaches distal areas | | **Day 7–8** | Fades in order of appearance | Face clears first; extremities last | ### Clinical Features of the Exanthem **High-Yield:** The measles rash is **maculopapular**, **blanching** initially, and becomes **confluent** on the trunk. It fades in the same order it appeared (cephalocaudal clearance). **Clinical Pearl:** The rash typically appears 3–4 days after fever onset, coinciding with the disappearance of Koplik spots. The presence of rash + Koplik spots together is rare; as the rash emerges, Koplik spots fade. ### Mnemonic for Measles Rash Progression **"Face → Trunk → Feet"** — Remember the rash spreads **downward** from head to toe, not in reverse. ### Differential Timing - **Rubella:** Rash also spreads cephalocaudally but is **finer**, **non-confluent**, and **transient** (clears in 3 days) - **Varicella:** Rash appears in **crops** on trunk first, then spreads; lesions are **vesicular** with different stages simultaneously - **Scarlet fever:** Rash is **sandpaper-like**, appears on trunk/neck first, and **spares palms/soles** [cite:Park 26e Ch 8]