Measles (Rubeola) is a highly infectious disease that is caused by the measles virus. There are two phases of disease: a catarrhal (prodromal) stage and an exanthem stage. The catarrhal stage is characterized by a fever with conjunctivitis, coryza, cough, and pathognomonic Koplik spots on the buccal mucosa. The sudden development of a high fever, malaise, and exanthem represents the next phase. The exanthem stage is typically characterized by an erythematous maculopapular rash that originates behind the ears and spreads to the rest of the body towards the feet. Infection is usually self-limiting and followed by lifelong immunity. Disease management includes vitamin A supplementation, symptomatic treatment, and possible post-exposure prophylaxis (PEP). Measles causes transient immunosuppression and may lead to serious complications such as encephalitis, otitis, or pneumonia. A rare but lethal late complication of measles is subacute sclerosing panencephalitis (SSPE), which may also affect immunocompetent individuals. Active immunization against measles is available in form of a combination vaccine against mumps and rubella (MMR). The first dose is recommended between the ages of 12 and 15 months and the second dose between 4 and 6 years of age or at least 28 days after the first dose. The prognosis is good in uncomplicated cases. However, newborns and immunocompromised patients are more likely to suffer from severe complications.
- Distribution: Measles typically occurs in regions with low vaccination rates and in resource-limited countries. 
- Peak incidence: < 12 months of age 
- ∼ 90%
- Highly contagious 4 days before and up to 4 days after the onset of exanthem.
Epidemiological data refers to the US, unless otherwise specified.
- Duration: ∼ 2 weeks after infection
Prodromal stage (catarrhal stage) 
- Duration: ∼ 4–7 days
Exanthem stage 
- Duration: ∼ 7 days (develops 1–2 days after enanthem)
- High fever, malaise
- Generalized lymphadenopathy
Erythematous maculopapular, blanching, partially confluent exanthem
- Begins behind the ears along the hairline
- Disseminates to the rest of the body towards the feet (palm and sole involvement is rare)
- Fades after ∼ 5 days of onset, leaving a brown discoloration and desquamation in severely affected areas
The cough may persist for another week and may be the last remaining symptom.
The most important findings of measles are the 3 Cs and 1 K: Coryza, Cough, Conjunctivitis, and Koplik spots.
Measles should be suspected in a patient with typical clinical findings. Laboratory tests are always necessary to confirm the diagnosis. 
- CBC: ↓ leukocytes, ↓ platelets
- Identification of pathogen: direct virus detection via reverse-transcriptase polymerase chain reaction (RT-PCR) possible
- Biopsy: affected lymph nodes show paracortical hyperplasia and Warthin-Finkeldey cells (multinucleated giant cells formed by lymphocytic fusion).
Subacute sclerosing panencephalitis (SSPE) 
- Definition: a lethal, generalized, demyelinating inflammation of the brain caused by persistent measles virus infection 
- Primarily affects males between 8 and 11 years of age
- Usually develops ≥ 7 years after measles infection
- Clinical presentation: characterized by four clinical stages
- Prognosis: SSPE leads to death within 1–3 years of diagnosis) 
Other complications 
- Bacterial superinfection
- Frequency: ∼ 1:1000 
- Develops within days of infection
- Acute disseminated encephalomyelitis may develop within weeks.
- Giant cell pneumonia (viral, most commonly seen in immunosuppressed individuals)
We list the most important complications. The selection is not exhaustive.
Postexposure prophylaxis (PEP)
- Indication: negative or indeterminate serology
- Further measures for contact persons: avoidance of communal facilities