Measles (Rubeola)

Measles is a highly contagious, vaccine-preventable viral illness caused by the measles virus (family Paramyxoviridae) that classically presents with fever, the "three Cs" (cough, coryza, conjunctivitis), and a cephalocaudal maculopapular rash. [1-2] Approximately 25% of patients require hospitalization, and complications occur in ~30% of cases. [1][3] The following figure illustrates the clinical features and disease timeline:

• Key HPI questions: Onset and duration of fever, rash characteristics and progression (face → trunk → extremities), presence of cough, runny nose, red/watery eyes, oral lesions
• Symptom characterization: Prodrome of 2–4 days with high fever (up to 40.6°C/105°F), malaise, and the three Cs, followed by rash onset 3–5 days later [2-3]
• Timing/triggers: Incubation period averages 10–14 days (range 7–23) from exposure to prodrome; rash appears ~14 days post-exposure [1][3]
• Associated symptoms: Diarrhea (early, may persist up to 1 month), photophobia, anorexia, malaise [1]
• Important negatives: Vaccination history (number of MMR doses and dates), recent international travel or travel to outbreak areas, known measles exposure within 21 days, immunocompromised state [4-5]

• Respiratory distress — tachypnea, hypoxia, crackles (pneumonia is the most common cause of measles hospitalization and death) [1]
• Altered mental status, seizures, focal neurologic deficits → suspect encephalitis (~1 per 1,000 cases, 20% mortality) [2][6]
• Severe dehydration from persistent diarrhea/poor oral intake
• Signs of secondary bacterial sepsis — persistent high fever after rash onset, toxic appearance
• Corneal ulceration/visual changes — especially in vitamin A–deficient patients [6]
• Immunocompromised patients — may lack rash entirely, at risk for giant-cell (Hecht's) pneumonia (often fatal) and measles inclusion-body encephalitis (100% mortality) [1-2]
• Pregnancy — risk of spontaneous abortion, premature labor, maternal respiratory complications [6]

• No approved antiviral therapy exists for measles [1-2]
• Vitamin A (AAP/WHO-recommended, age-based dosing — see Treatment Plan below) — reduces mortality by 34–50% in children [1][7]
• Ribavirin — shows in vitro activity; not FDA-approved for measles; has been used off-label in severe/immunocompromised cases [4][8]
• Antibiotics — only if secondary bacterial infection (pneumonia, otitis media, sepsis) is identified; not recommended empirically [2]
• Antipyretics — acetaminophen or ibuprofen for fever/discomfort
• Contraindicated: Aspirin in children (Reye syndrome risk); high-dose vitamin A in pregnancy (teratogenic) [5]
• Post-exposure prophylaxis (PEP): MMR vaccine within 72 hours of exposure, or immunoglobulin (IG) within 6 days for those who cannot receive vaccine (infants <6 months, pregnant women, immunocompromised) [5-6]

• Maintain adequate hydration — oral rehydration solutions for mild dehydration; IV fluids if unable to tolerate PO or severe diarrhea
• Small, frequent, soft meals during acute illness (stomatitis may limit intake)
• Vitamin A–rich foods during recovery (eggs, dairy, orange/yellow vegetables) — though pharmacologic supplementation is the priority acutely
• No specific dietary restrictions; focus on caloric maintenance to prevent measles-associated malnutrition [1]

• HEENT: Eye redness/discharge, photophobia, oral lesions (Koplik spots), ear pain/discharge, sore throat
• Respiratory: Cough (barking vs. productive), dyspnea, chest pain
• GI: Diarrhea (frequency, volume), vomiting, abdominal pain, oral intake
• Neurologic: Headache, confusion, seizures, focal weakness
• Constitutional: Fever pattern, weight loss, fatigue
• Skin: Rash onset location, spread pattern, pruritus, desquamation

• Vaccination records of patient and household contacts — critical for determining immunity and PEP eligibility [5]
• Exposure history: Daycare, school, healthcare facility, travel (especially international), contact with known cases
• Household contacts who are immunocompromised, pregnant, or unvaccinated infants — high-risk for severe disease
• Immigration history — recent arrival from endemic areas increases pre-test probability [2]
• Community outbreak status — check with local/state health department

• Unvaccinated or incompletely vaccinated status (single most important risk factor) [5]
• Age: <5 years and >20 years at highest risk for complications [2][4]
• Immunocompromised: HIV/AIDS, active chemotherapy, organ transplant recipients, congenital immunodeficiency [2]
• Pregnancy [4][6]
• Vitamin A deficiency and malnutrition [1][6]
• International travel or contact with travelers from endemic regions [4]
• Born between 1957–1989 with only one MMR dose (suboptimal immunity)

• Rubella — milder prodrome, postauricular/suboccipital lymphadenopathy, shorter rash duration, no Koplik spots [2]
• Parvovirus B19 (fifth disease) — "slapped cheek" rash, reticular lace-like rash on extremities, no conjunctivitis [2]
• Roseola (HHV-6) — rash appears after fever resolves (opposite of measles) [9]
• Scarlet fever — sandpaper-textured rash, strawberry tongue, pharyngitis, Pastia lines [9]
• Kawasaki disease — prolonged fever, conjunctival injection without exudate, mucositis, extremity changes, lymphadenopathy (children <5 years)
• Drug reaction — temporal relationship to medication, eosinophilia
• Dengue/Zika/Chikungunya — travel to endemic areas, arthralgia, thrombocytopenia [6]
• Acute HIV seroconversion — morbilliform rash, oral ulcers, lymphadenopathy [10]
• Meningococcemia — cannot-miss; petechial/purpuric rash, rapid deterioration [11]

• Prior measles infection (confers lifelong immunity)
• Number and dates of MMR vaccinations
• Immunosuppressive conditions or medications (biologics, chemotherapy, chronic steroids)
• History of vitamin A deficiency or malabsorption syndromes
• Pregnancy status in women of childbearing age
• Prior episodes of febrile exanthems
• Chronic lung disease (increases pneumonia risk)

• Vitals: High fever (often ≥40°C/104°F), tachycardia; assess for tachypnea/hypoxia (pneumonia)
• HEENT:
  • Koplik spots — small bluish-white plaques on buccal mucosa (pathognomonic; present in 60–70% of cases, appear 1–2 days before rash) [1-2][4]
  • Bilateral non-purulent conjunctivitis
  • Rhinorrhea, pharyngeal erythema
  • Otoscopic exam for otitis media
• Skin: Erythematous maculopapular rash starting at hairline/face → trunk → extremities; may become confluent on face/upper body; initially blanching, later brownish with desquamation [2][4]
• Lungs: Crackles, rhonchi, decreased breath sounds (pneumonia)
• Neuro: Mental status, meningeal signs, focal deficits (if encephalitis suspected)
• Lymph nodes: Generalized lymphadenopathy may be present

• Measles-specific IgM (serum) — sensitivity 83–98.8%, specificity 93.7–100%; may be negative in first 72 hours after rash onset; repeat if initially negative [2][4][12]
• Measles RT-PCR (NP or throat swab ± urine) — sensitivity 94%, specificity 99%; detectable ~3 days after rash onset; preferred early test [2][4]
• Urine PCR — adding urine to NP/throat swab improves sensitivity [4-5]
• CBC — leukopenia (especially lymphopenia) is common; may see secondary leukocytosis with bacterial superinfection
• CMP/BMP — assess hydration status, electrolytes (diarrhea/dehydration)
• Blood cultures — if secondary bacterial infection suspected
• CRP/procalcitonin — to help differentiate viral vs. bacterial complications
• Vitamin A levels are not routinely needed before supplementation [3]

• Chest X-ray — indicated if respiratory distress, hypoxia, or clinical suspicion for pneumonia; findings may include interstitial infiltrates, lobar consolidation, or hilar lymphadenopathy [6]
• CT chest — rarely needed; consider for severe or atypical pneumonia in immunocompromised patients
• MRI brain — indicated if neurologic symptoms; acute disseminated encephalomyelitis (ADEM) shows T2/FLAIR hyperintensities in white matter [6]
• Imaging is unnecessary in uncomplicated measles

• CDC case definition: Generalized maculopapular rash + fever ≥38.3°C + cough, coryza, or conjunctivitis — sensitivity 75–90%, but low positive predictive value in low-incidence settings [2]
• Viral genotyping — performed by public health labs for epidemiologic tracking; not needed for clinical management [2]
• IgG avidity assay — distinguishes primary infection from secondary immune response in previously vaccinated individuals [6]
• CSF measles antibodies — indicated if SSPE suspected; compare CSF:serum ratio to confirm intrathecal synthesis [12]
• Lumbar puncture — if encephalitis suspected

• Myocarditis is a rare complication of measles; obtain ECG if chest pain, new heart failure symptoms, or unexplained tachycardia
• Look for: ST-segment changes, low voltage, conduction abnormalities, arrhythmias
• Routine ECG is not indicated in uncomplicated measles

Clinical summary: Measles is one of the most contagious human diseases (R₀ = 12–18), transmitted via airborne droplets and remaining infectious in air for up to 2 hours. Patients are contagious from 4 days before to 4 days after rash onset. [1-2]

Severity stratification

• Uncomplicated: Self-limited; fever + rash + three Cs resolving within 7 days of rash onset [2]
• Complicated: Pneumonia (1–6%), otitis media (7–9%), diarrhea (8–10%), encephalitis (~1/1,000), death (~1–3/1,000 in developed countries) [1-2]
• Atypical presentations: Modified measles in previously vaccinated (milder/absent symptoms); absent rash in immunocompromised [6]

Immune amnesia: Measles causes immunosuppression lasting 2–3 years, increasing susceptibility to secondary infections — a critical counseling point. [4]

Initial stabilization

• Immediate airborne isolation (negative-pressure room if available; N-95 mask for all staff) [5][13]
• IV access and fluid resuscitation if dehydrated
• Supplemental O₂ if hypoxic

Vitamin A supplementation (AAP/WHO — 2 oral doses on consecutive days): [2-3][7]

A third age-specific dose at 2–4 weeks if clinical signs of vitamin A deficiency (xerophthalmia, Bitot spots). [2-3] Avoid high-dose vitamin A in pregnancy. [5]

Supportive care

• Antipyretics (acetaminophen/ibuprofen) for fever
• Oral or IV rehydration for diarrhea/dehydration
• Antibiotics only for confirmed secondary bacterial infections (pneumonia, otitis media, sepsis) [2]

Post-exposure prophylaxis for contacts: [5]

• MMR vaccine within 72 hours of exposure (for eligible contacts ≥6 months without evidence of immunity)
• Immunoglobulin (IG) within 6 days for infants <6 months, pregnant women, and immunocompromised individuals who cannot receive live vaccine

Mandatory reporting: Notify local/state health department immediately upon clinical suspicion — do not wait for lab confirmation. [2][5]

Admission criteria

• Respiratory distress, hypoxia, or pneumonia
• Severe dehydration or inability to tolerate oral fluids
• Neurologic symptoms (altered mental status, seizures)
• Immunocompromised patients
• Pregnant patients with complications
• Infants <12 months with moderate-to-severe illness
• Social concerns (inability to isolate at home)

Discharge criteria

• Clinically stable, tolerating oral fluids, no respiratory distress
• Able to self-isolate at home for 4 days after rash onset
• Reliable follow-up arranged

Observation indications

• Borderline cases with mild dehydration or early respiratory symptoms
• Young children (<5 years) or adults (>20 years) given higher complication rates

Specialist consultation triggers

• Pulmonology/ICU for severe pneumonia or respiratory failure
• Neurology for encephalitis or seizures
• Ophthalmology for keratitis or corneal ulceration
• Infectious disease for immunocompromised patients
• OB/GYN for pregnant patients [4][6]

Follow-up timing

• Primary care follow-up within 48–72 hours of ED discharge
• Recheck at 1–2 weeks to assess for late complications (pneumonia, otitis media)
• Immunocompromised patients require closer surveillance

Return immediately for

• Worsening or new-onset difficulty breathing, chest pain
• Persistent high fever (>5 days after rash onset) or fever recurrence after initial improvement
• Confusion, severe headache, seizures, neck stiffness
• Inability to keep fluids down, signs of dehydration (decreased urine output, dry mucous membranes)
• Eye pain, vision changes, or purulent eye discharge
• Ear pain or drainage

Patient counseling

• Isolation: Remain home and avoid contact with others for 4 days after rash onset [2]
• Notify anyone who may have been exposed (especially unvaccinated, pregnant, immunocompromised contacts)
• Expected course: fever resolves 2–3 days after rash onset; rash fades over 5–7 days in order of appearance; full recovery in uncomplicated cases within ~7–10 days [2]
• Immune amnesia — increased susceptibility to other infections for up to 2–3 years; ensure all other vaccinations are up to date [4]
• Ensure household contacts have evidence of immunity or receive PEP [5]

1. Measles 2025. — Do LAH, Mulholland K. The New England Journal of Medicine. 2025.

2. Measles. — Strebel PM, Orenstein WA. The New England Journal of Medicine. 2019.

3. Measles (Rubeola). — James L. Goodson and Thomas D. Filardo CDC Yellow Book. 2025.

4. Measles. — Stoneman EK. The Journal of the American Medical Association. 2025.

5. Expanding Measles Outbreak in the United States and Guidance for the Upcoming Travel Season. — United States Centers for Disease Control and Prevention (2025). 2025.

6. Measles. — Hübschen JM, Gouandjika-Vasilache I, Dina J. Lancet. 2022.

7. Measles and Measles Vaccination: A Review. — Bester JC. JAMA Pediatrics. 2016.

8. Acute Management of Measles: A Systematic Review of Therapeutic Strategies. — Kaur A, Alaribe U, Varon J, Hassaan S, Halma M. Antiviral Research. 2026.

9. Common Skin Rashes in Children. — Allmon A, Deane K, Martin KL. American Family Physician. 2015.

10. Post-Travel Dermatologic Conditions. — Karolyn A. Wanat and Scott A. Norton CDC Yellow Book. 2025.

11. Clinical Features, Diagnosis, and Management of Enterovirus 71. — Ooi MH, Wong SC, Lewthwaite P, Cardosa MJ, Solomon T. The Lancet. Neurology. 2010.

12. Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2024 Update by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM). — Miller JM, Binnicker MJ, Campbell S, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2024.

13. An Update and Review of Measles for Emergency Physicians. — Alves Graber EM, Andrade FJ, Bost W, Gibbs MA. The Journal of Emergency Medicine. 2020.