Snapshot A 12-year-old boy is brought to the emergency room for cough, high fever, and rash. He also reports having itchy eyes for the past day. The rash started on his head and neck and traveled downward towards his trunk. His vaccination history is unknown. On physical exam, he has a confluent maculopapular rash that is blanching with pressure. There are blue-white macules overlying a background of erythema on the buccal mucosa. He is immediately isolated and admitted to the hospital for supportive care and vitamin A supplementation. Introduction Classification measles (rubeola) virus a paramyxovirus an enveloped, helical capsid, linear, single-stranded, negative-sense RNA virus highly contagious via respiratory secretions causes measles Epidemiology incidence decreased in the US due to vaccination endemic in parts of Europe, Africa, and Asia demographics more common in children risk factors lack of vaccination travel to endemic areas Pathogenesis all paramyxoviruses contain the F (fusion) protein can induce cell-to-cell fusion, creating multi-nucleated giant cells helps mediate virus and cell membrane fusion, ultimately resulting in infection of the host cell hemagglutinin (HA) protein helps the virus attach to the host cell the virus replicates in epithelial cells in the respiratory tract and lymph nodes Prevention measles, mumps, and rubella (MMR) vaccine given over 2 doses Prognosis prodrome followed by rash Presentation Symptoms prodrome high-grade fever Cough Conjunctivitis Coryza rash Physical exam Koplik spots buccal mucosa with bluish-white macules with background of bright red pathognomonic for measles confluent maculopapular rash starts in the head and neck and spreads downward to trunk initially blanching with pressure in the first few days lymphadenopathy Studies Labs detection of measles-specific immunoglobulin M or G detection of virus on reverse transcriptase-polymerase chain reaction Biopsy of lymph node Warthin-Finkeldey giant cells, or fused lymphocytes, with paracortical hyperplasia Making the diagnosis based on clinical presentation and confirmed with laboratory studies Differential Parvovirus B19 infection distinguishing factors slapped cheek rash maculopapular rash on trunk and limbs that does not spread from head/neck downward Treatment Management approach mainstay of treatment is supportive care and prevention with vaccines Conservative supportive care indication all patients modalities anti-pyretics analgesics hydration Medical vitamin A indication reduces morbidity and mortality in all patients Complications Subacute sclerosing panencephalitis in adulthood neurodegenerative disease characterized by seizures Encephalitis Giant cell pneumonia in the immunosuppressed