Measles Rash Distribution on the Scalp
Yes, measles can occur on the scalp and top of the head, as the characteristic rash spreads from the face downward to cover the entire body, including hair-bearing areas.
Rash Distribution Pattern
The measles rash follows a predictable cephalocaudal (head-to-toe) progression that includes the scalp:
- The rash begins on the face and behind the ears, then spreads downward to the trunk and out to the extremities over the course of several days 1, 2
- The rash becomes more confluent as it spreads from head to toe, meaning it can cover all areas of the head including the scalp 3
- The maculopapular or morbilliform rash typically appears 3-4 days after the onset of prodromal symptoms (fever, cough, coryza, conjunctivitis) 1, 4
Clinical Presentation Timeline
Understanding the full disease progression helps identify measles:
- Prodromal phase: Fever with the "three C's" (cough, coryza, conjunctivitis) appears first, lasting 2-4 days before the rash 2, 5
- Koplik spots (pathognomonic white spots on red background inside the mouth) appear during the prodrome before the rash emerges 1, 2
- Rash phase: The erythematous maculopapular rash starts on the face and spreads systematically downward, covering the body including the scalp within days 5, 3
- The rash appearance coincides with the peak of symptoms 4
Important Clinical Caveat
Immunocompromised patients may present atypically - they can develop measles without the typical rash pattern or even without any rash at all, making diagnosis more challenging 1, 2. This population requires heightened clinical suspicion based on exposure history and prodromal symptoms alone.
Diagnostic Confirmation
When measles is suspected based on the characteristic rash distribution (including scalp involvement):
- Immediate laboratory confirmation should be pursued through measles-specific IgM antibody testing or viral RNA detection 2, 3
- Airborne isolation precautions must be implemented immediately without waiting for laboratory results 5
- Public health notification is mandatory as measles is highly contagious from 4 days before rash onset to 4 days after 1, 2