Snapshot A 30-year-old woman presents to the emergency room. She is a tourist from Southeast Asia and reports having a low-grade fever for several days. She also reports having arthralgias, especially in her wrists and knees. Additionally, she has a pink rash on her face and her chest. The rash appears to be spreading downward. She does not recall whether or not she had the measles, mumps, and rubella vaccine. On physical exam, she has lymphadenopathy in her postauricular and posterior cervical chains. She also has petechiae on her soft palate and uvula and a pink maculopapular rash on her face and trunk. Isolation precautions are indicated. Introduction Classification rubella virus an enveloped, icosahedral capsid, single-stranded, positive-sense RNA virus a togavirus causes rubella (German (3-day) measles) transmission via respiratory secretions Prevention measles, mumps, and rubella (MMR) vaccine given over 2 doses Epidemiology Incidence decreased in the US due to vaccination endemic in other parts of the world Demographics any age can be affected Risk factors lack of vaccination travel to or from endemic areas ETIOLOGY Pathogenesis the virus replicates in the upper respiratory tract and lymph nodes it then disseminates throughout the body can spread through the placenta to cause vertical transmission may result in miscarriage or congenital rubella syndrome Associated conditions congenital rubella syndrome blueberry muffin appearance dermal extramedullary hematopoiesis cataracts deafness congenital heart disease Presentation Symptoms low-grade fever polyarthritis and polyarthralgia more common in adult females fingers, wrists, and knees are most commonly involved Physical exam lymphadenopathy before the rash postauricular lymphadenopathy is classic may also have posterior cervical and suboccipital lymphadenopathy fine, pink, non-confluent maculopapular rash starts on face and spreads to trunk and extremities may be itchy desquamates rash resolves in 3 days petechial rash on soft palate (Forschheimer spots) orchitis Studies Labs detection of rubella-specific immunoglobulin M or G detection of virus on reverse transcriptase-polymerase chain reaction Differential Parvovirus B19 infection distinguishing factors slapped cheek rash maculopapular rash on trunk and limbs that does not spread from head/neck downward Measles distinguishing factors confluent maculopapular rash coryza and Koplik spots DIAGNOSIS Making the diagnosis based on clinical presentation and confirmed with laboratory studies Treatment Management approach mainstay of treatment is supportive care and prevention with vaccines Conservative supportive care indication all patients modalities antipyretics analgesics hydration Complications Vertical transmission to fetus congenital rubella syndrome Thrombocytopenic purpura Guillain-Barre syndrome Prognosis Infection may be asymptomatic but still contagious