What are the characteristics and treatment of measles, particularly in unvaccinated children and young adults?

Measles: Clinical Characteristics and Management

Clinical Presentation

Measles is characterized by a prodrome of high fever, cough, coryza (runny nose), and conjunctivitis ("the three Cs"), followed 3-4 days later by a maculopapular rash that begins on the face and spreads downward to the trunk and extremities. 1

Pathognomonic Features

• Koplik spots (small white spots on a red background inside the mouth) appear during the prodrome and are pathognomonic for measles, providing diagnostic opportunity before rash emergence 1, 2
• The incubation period averages 10-12 days from exposure to prodrome and 14 days from exposure to rash (range: 7-18 days) 1, 3
• Patients are contagious from 4 days before rash onset to 4 days after rash appears 1, 3

Common Complications

• Diarrhea is the most common complication 1
• Pneumonia is the most common cause of measles-related death 4, 2
• Otitis media (middle ear infection) occurs frequently 1
• Acute encephalitis occurs in approximately 1 per 1,000 cases and represents a leading cause of mortality 1, 4
• Death occurs in 1-2 per 1,000 reported cases in the United States 1, 4

High-Risk Populations

Increased Mortality Risk

• Infants and young children face higher mortality risk than older children 1, 4
• Adults experience higher complication rates, with 25% requiring ≥1 day of hospitalization 5
• Pregnant women experience increased rates of premature labor, spontaneous abortion, and low birth weight infants 5, 1
• Immunocompromised individuals (including those with HIV, leukemia, lymphoma, or on high-dose corticosteroids ≥20 mg/day prednisone for >2 weeks) may develop severe, prolonged infection, sometimes without typical rash 1, 4

Treatment and Management

Vitamin A Supplementation

The American Academy of Pediatrics recommends vitamin A supplementation for ALL children with clinical measles: 1

• Children under 12 months: 100,000 IU orally
• Children over 12 months: 200,000 IU orally
• Repeat dose on day 2 for children with complicated measles
• Additional dose 1-4 weeks later for those with vitamin A deficiency eye symptoms

Supportive Care

• Oral rehydration therapy for diarrhea 1
• Antibiotics ONLY for secondary bacterial infections, particularly pneumonia—not for viral pharyngitis itself 1
• Supportive care for fever, cough, and other symptoms 2, 6

Isolation and Infection Control

• Implement immediate airborne precautions when measles is suspected 1, 3
• All staff caring for measles patients should use N95 respirators regardless of immunity status due to ~1% vaccine failure rate 3
• Report all suspected cases immediately and obtain laboratory confirmation with measles-specific IgM antibody testing and RT-PCR 1, 6

Prevention

Vaccination Strategy

The CDC recommends MMR vaccine as the cornerstone of measles prevention: 1

• First dose at 12-15 months of age
• Second dose at 4-6 years of age
• All adults born in 1957 or later without documented immunity should receive at least one dose 5

Post-Exposure Prophylaxis

• MMR vaccine within 72 hours of exposure may provide protection or modify disease 1, 3
• Immune globulin (IG) 0.25 mL/kg IM (maximum 15 mL) within 6 days of exposure can prevent or modify infection when vaccine is contraindicated 3

Special Populations

• HIV-infected children without severe immunosuppression should receive MMR vaccine at 12 months, with consideration for second dose as early as 28 days later 1
• Children with severe immunosuppression should NOT receive measles vaccination due to risk of vaccine-associated disease 1
• Undernutrition is NOT a contraindication—it should be considered a strong indication for vaccination 1

Critical Pitfalls to Avoid

• Do not assume persons born before 1957 are immune—up to 9.3% of healthcare workers born before 1957 lack immunity 5, 4
• Do not prescribe antibiotics for measles-associated pharyngitis unless documented secondary bacterial infection is present 1
• Do not delay isolation measures—implement airborne precautions immediately when Koplik spots are identified 1
• Exclude exposed healthcare workers without immunity from work days 5-21 after exposure 3