The child with a fever and rash in your Emergency Department (ED) may actually have measles. This year, there have been 1,182 cases of measles in the U.S., and counting. This is the highest rate in the past 27 years [1]. Globally, measles kills over a hundred thousand children [2]. In the U.S., one child dies for about every 1,000 cases [3]. Emergency providers must be able to quickly detect short-term complications that can lead to death and distinguish measles from mimics like Kawasaki Disease. It’s no coincidence that this year’s outbreak is in the setting of lower vaccination rates. The CDC now has new vaccine recommendations, and it’s imperative that ED providers join forces with public health providers to prevent future measles cases and deaths (photo credit).


Measles continues to present as we all learned in medical school: the “classic” prodrome of fever, conjunctivitis, and URI symptoms followed by a maculopapular rash 3 to 4 days later that spreads cephalocaudal and spares the palms and soles. The pathognomonic Koplik spots in the mouth only appear in about 5% of cases. Individuals are infectious 4 days before and 4 days after the onset of the rash, and the incubation period for the virus can last up to three weeks. The median age for measles is 5 years old, but it can also impact unvaccinated adults [4].

Some vaccinated adults may also be susceptible. In the late 1960s, children received a killed version of the vaccine that led to insufficient protection. Patients who received this vaccine had a modified measles presentation: the rash started in the extremities, affected the palms and soles, and was not contagious [2].​​ However, because the current vaccine is an attenuated virus (and a lot more effective), this alternative presentation is no longer seen in children. 

Measles Complications 

Part of an ED provider’s role is to think ahead. This year, 10.5% of children with measles have been hospitalized [1]. An important and dreaded complication from measles is neurologic such as acute disseminated encephalomyelitis, which occurs in 1 in 1,000 cases. The most lethal complication, however, is pneumonia. It accounts for 30% of pediatric measles hospitalizations and contributes to 60% of measles associated deaths [2].​​ Based on data from prior years, other important things to look out for is dehydration (over 70% of hospitalizations) and otitis media (40% of hospitalizations) [5].

Ordering CRP and LDH 

When a child presents with a rash, unless you’re a dermatologist, they all sort of look the same. It can be hard to tell if a child’s red eyes are related to the rash, or if it’s because they rubbed their eyes after touching everything around them.  

Measles and Kawasaki Disease (KD) can both have fever, conjunctivitis, and a rash, and thus can be confused for each other. An international study found that an LDH of more than 800mg/dl had a sensitivity of 89% and a specificity of 90% for Measles, while a CRP of more than 3mg/dl had sensitivity of 89% and a specificity of 85% for KD [4]. Although this study was not conducted in the U.S, these labs can help tease out the differential diagnosis in the ED.  

Public Health in the ED

71% of children affected by this year’s outbreak were unvaccinated, and 18% had an unknown vaccination status. Vaccines work. Only 3% of vaccinated patients ultimately contract measles if subsequently exposed. This is compared to an up to 90% chance of measles if unvaccinated [6].

Vaccinations naturally come up in a pediatric ED visit, especially in the past medical history and review of systems. This offers a natural opportunity to speak with families about vaccination, learn about families’ unique perspectives, and address any concerns. ED providers often have the undivided attention of concerned parents. Even if just for several minutes, having honest, empathetic, and informed discussions can be the first step to increasing vaccination rates. For some families in the U.S., the ED is the only source of health care; these conversations can save lives. 

Updated Vaccine Recommendations

In light of the outbreak, the CDC has recommended infants ages 6-11 months who are traveling internationally or to an area with a measles outbreak to obtain one dose of the MMR vaccine [1, 6]. This vaccine is very safe; the most common side effect is mild fever and pain at the injection site [2].​​ At 12 months, children should still receive the standard MMR vaccine sequence [1, 6].

If you’re concerned your patient has had a measles exposure or you want to counsel the rest of the family of a patient with measles, post-exposure recommendations are as follows: 

  • if an infant is less than 6 months, immunoglobulin should be given within 6 days
  • if an infant is between 6 and 11 months, you have two options: the MMR vaccine administered within 72 hours or immunoglobulin within 6 days.
  • if an infant has received immunoglobulin, wait at least 6 months to administer the MMR vaccine  

Immunoglobulin has been found to reduce the risk of contracting measles by 72%. However, it should never be used in place of a vaccine [2].


More and more children are presenting to hospitals with measles and ED providers are in a unique position to diagnose measles and its complications, and promote public health through preventative and post-exposure vaccinations.


  1. Centers for Disease Control and Prevention.  Measles (Rubeola). Centers for Disease Control and Prevention. Published August 12, 2019. Accessed August 17, 2019.
  2. Leung A, Hon K, Leong K, Sergi C. Measles: a disease often forgotten but not gone. Hong Kong Med J. 2018;24(5):512-520.
  3. Centers for Disease Control and Prevention. Measles Data and Statistics. Published April 16, 2019. Accessed August 27, 2019.
  4. Buonsenso D, Macchiarulo G, Supino M, et al. Laboratory Biomarkers to Facilitate Differential Diagnosis between Measles and Kawasaki Disease in a Pediatric Emergency Room: A Retrospective Study. Mediterr J Hematol Infect Dis. 2018;10(1):e2018033.
  5. Hester G, Nickel A, LeBlanc J, et al. Measles Hospitalizations at a United States Children’s Hospital 2011-2017. Pediatr Infect Dis J. 2019;38(6):547-552.
  6. Jenco M. CDC updates measles vaccination guidance for infants traveling to U.S. outbreak areas. AAP Gateway. Published May 22, 2019. Accessed August 17, 2019.
Carolina Ornelas

Carolina Ornelas

Medical Student
University of California, San Francisco
Graduate Student
University of California, Berkeley School of Public Health
Carolina Ornelas

Latest posts by Carolina Ornelas (see all)

Dina Wallin, MD

Dina Wallin, MD

ALiEM Series Editor, The Leader's Library
Co-Medical Director of Pediatric Emergency Medicine,
Zuckerberg San Francisco General Hospital;
Director of Didactics, SFGH-UCSF Emergency Medicine Residency;
Assistant Clinical Professor of Emergency Medicine and Pediatrics,
University of California San Francisco