What is the diagnosis of a patient who presents with cough, high fever, runny nose, conjunctivitis, and an erythematous macular papular rash that spreads from the face to the trunk to extremities?

Measles (Rubeola)

The diagnosis is measles (rubeola), a highly contagious viral illness characterized by the classic triad of cough, coryza (runny nose), and conjunctivitis, followed by high fever and a pathognomonic erythematous maculopapular rash that begins on the face and spreads cephalocaudally to the trunk and extremities. 1, 2

Clinical Presentation Algorithm

The diagnosis of measles follows a characteristic temporal pattern that distinguishes it from other febrile rash illnesses:

Prodromal Phase (Days 1-4)

• High fever (typically 101-104°F) with acute onset 1, 3
• The "three C's": Cough, Coryza (runny nose), and Conjunctivitis - this triad is pathognomonic for measles 3, 4, 5
• Koplik spots may appear on the buccal mucosa during this phase (small white spots with red halos, considered pathognomonic when present) 1, 4, 2

Rash Phase (Days 3-7)

• Erythematous maculopapular (morbilliform) rash appears 2-4 days after fever onset 1, 2, 5
• Characteristic progression: Begins on the face and behind the ears, then spreads downward to the trunk and out to the extremities 1, 2
• Rash appearance coincides with peak of symptoms 4

Distinguishing Measles from Rubella

While both present with maculopapular rash and fever, critical differences exist:

Measles has:

• Prominent respiratory symptoms (cough, coryza) 3, 5
• Conjunctivitis (often with subconjunctival hemorrhage) 6, 3
• Higher fever 3, 7
• Koplik spots (when present) 1, 4

Rubella has:

• Arthralgia/arthritis or lymphadenopathy as distinguishing features 1
• Milder constitutional symptoms 1
• Lower fever threshold (>99.0°F vs 101-104°F) 1

Cases meeting the measles case definition are specifically excluded from rubella diagnosis 1

Immediate Management Priorities

Isolation and Infection Control

• Immediate airborne isolation is mandatory - patients are contagious from 4 days before rash to 4 days after rash onset 1, 2
• Healthcare workers require N-95 masks and airborne infection isolation rooms 3, 2
• Remove from patient contact immediately if healthcare worker develops prodromal symptoms 1

Laboratory Confirmation

• Serum measles IgM antibody is the most common confirmatory test 3, 2
• Throat swab for viral RNA detection by PCR 7
• All suspected cases require laboratory confirmation - clinical diagnosis alone is insufficient 2

Public Health Notification

• Immediately inform local public health department and hospital infection control of suspected cases 2
• Measles is a reportable disease requiring urgent public health response 1

Critical Complications Requiring Monitoring

Pneumonia is the most lethal complication and accounts for most measles-associated morbidity and mortality 4, 5

Other serious complications include:

• Encephalitis
• Secondary bacterial infections
• Dehydration and nutritional deficiencies 4

Treatment Approach

Supportive Care

• Vitamin A supplementation is essential in management 4, 5
• Correction of dehydration and nutritional deficiencies 4
• Treatment of secondary bacterial infections 4

Special Populations Requiring Aggressive Management

Patients who are pregnant, immunocompromised, or unvaccinated may require:

• Measles vaccine (if appropriate timing)
• Intravenous immunoglobulin
• Ribavirin in severe cases 3

Common Pitfalls to Avoid

• Do not confuse with rubella - the prominent respiratory symptoms (cough, coryza) and conjunctivitis distinguish measles from rubella 3, 5
• Do not delay isolation - measles is airborne and highly contagious (one of the most contagious diseases known) 3, 5
• Do not assume vaccination equals immunity - up to 5% of people who received a single vaccine dose have primary vaccine failure 1
• Do not miss Koplik spots - their presence during the prodrome allows diagnosis before rash appears 1, 4