Core Dermatology Diagnoses / CategoriesInfectious

Rubella

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Publish date: Posted on
Last updated: May 11, 2022

Keywords #

rubella
togavirus
morbilliform rash

Diagnosis #

Rubella most commonly affects children. Rubella manifests  as an acute-onset morbilliform rash consisting of pin-point pink macules and papules that do not darken or coalesce. , The exanthem characteristically begins on the face and spreads downward to the trunk and extremities within 24h Skin findings typically occur without severe systemic symptoms, but low grade fever and lymphadenopathy preferentially affecting the posterior cervical, posterior auricular, and suboccipital nodes may occur up to 5 days prior to the exanthema In adults, the exanthem can be accompanied by  more severe and protracted systemic symptoms (malaise, arthalgias, fevers, etc.). [1]

Key Concepts #
  • Rubella closely resembles multiple other childhood exanthems due to its maculopapular appearance with low grade fever and lymphadenopathy; specifically Roseola, Scarlet Fever, and Parvovirus. Wide rates of vaccination and US eradication make Rubella less likely, so consider other causes first and inquire as to vaccination status.
  • Primary infection in an adult is less common but more severe and accompanied by arthralgias 70% of the time; this symptom may persist as long as 1m following the initial illness.[2]
  • The dermatologic manifestations of this exanthem include a pink, pinpoint maculopapular rash that begins on the face and spreads caudally to trunk and limbs; prodromal symptoms may occur but are not always present.
  • Congenital Rubella is a syndrome including but not limited to hearing loss, intellectual disability, cardiac defects, and ocular defects.
  • Complications are infrequent and more common in adult population than pediatric. Postinfectious encephalitis (thought to be immune-mediated) occurs in 1/6000 cases, but has a generally good prognosis.
Epidemiology #

Rubella is a togavirus that was first isolated in 1962, allowing for vaccine development by 1970. It is acquired via inhalation of particles, with initial replication occurring in nasopharyngeal cells and regional lymph nodes. Infectious individuals may shed the virus for 2 weeks prior to clinical emergence.[3] It is estimated that 12million Americans contracted Rubella in 1964-65 (its putative epidemiological peak; incidence 58/100,000). This declined to 0.5 per 100,000 following the start of vaccination. [4] By 2004, Rubella was declared to be eliminated from the US. Globally, rubella still exists; highest incidence rates are reported in Africa and Southeast Asia where access to vaccination may remain limited.

Clinical Features #
  • Prodromal symptoms of fever, myalgias, arthralgias, malaise 1-5d prior to rash onset.
  • Lymphadenopathy in posterior auricular nodes, posterior cervical, and suboccipital nodes that may appear 1-5d prior to rash OR concurrently with rash.[5]
  • Pinpoint, pink maculopapular rash that begins on face and spreads rapidly caudally over 24h.[6]
  • Much more common in pediatric population; if in adult population, often accompanied by more severe systemic prodrome and longer duration.
Differential Diagnoses #
Diagnostic Workup #

Rubella should be considered only if there is clinical suspicion for lack of vaccination, as in 2021 this disease has been eliminated in the US and another diagnosis is probably more likely.

Laboratory tests are often unrevealing. ELISA for rubella-specific IgM antibodies may be performed. The antibody may be detected as early as 4 days after the onset of the rash, and will likely remain detectable in serum for up to 8 weeks following.[7]

If the patient is pregnant, viral particles may be isolated from nasopharyngeal swabs. Congenital infection can be isolated from cord blood, but this is not often performed due to cost.

Treatment #

Supportive care. There is no specific indicated therapy other than palliation of symptoms with antipyretics or analgesics for prodromal accompaniment. The rash will self-resolve without scarring. Focus has been, and should remain on prevention with the MMR vaccine.[8]

References #
  1. Gershon AA. Rubella virus. In: Principles and Practices of Infectious Diseases, Third Edition, Mandell GL, Douglas Jr RG, Bennett JE (Eds), Churchill Livingstone, New York 1990. p.1242.
  2. Rubella. In: Epidemiology and Prevention of Vaccine-Preventable Diseases, 12th Ed, Atkinson W, Wolfe C, Hamborsky (Eds), Public Health Foundation, Washington, DC 2011.
  3. American Academy of Pediatrics. Rubella. In: Red Book: 2018 Report of the Committee on Infectious Diseases, 31st ed, Kimberlin DW, Brady MT, Jackson MA, Long SS (Eds), American Academy of Pediatrics, Itasca, IL 2018. p.705.
  4. Plotkin SA. History of rubella and the recent history of cell culture. In: Vaccinia, Vaccination, Vaccinology: Jenner, Pasteur and their Successors, Plotkin S, Fantini B (Eds), Elsevier, Paris 1996. p.271.
  5. Gershon AA. Rubella virus. In: Principles and Practices of Infectious Diseases, Third Edition, Mandell GL, Douglas Jr RG, Bennett JE (Eds), Churchill Livingstone, New York 1990. p.1242.
  6. Cherry J, Baker A.. Rubella virus.. In: Feigin and Cherry’s Textbook of Pediatric Infectious Diseases, 8th ed., Cherry JD, Harrison GJ, Kaplan SL (Eds), Elsevier, Philadelphia 2019. p.1601.
  7. Best JM, Icenogle JP, Brown DWG. Rubella. In: Principles and Practices of Clinical Virology, 6th Ed, Zuckerman AJ, Banatvala JE, Schoub BD, et al (Eds), John Wiley & Sons, Ltd, West Sussex, UK 2009. p.561.
  8. Plotkin SA, Reef SE. Rubella vaccine. In: Vaccines, 5th Ed, Plotkin S, Orsenstein W, Offit P (Eds), Saunders Elsevier, Philadelphia 2008. p.735.
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