PetriKey

Disease

Measles

Rubeola: 3 C's, Koplik spots, descending rash

rubeolaairborneexanthemvaccine-preventableviral

High-yield clue

Cough, coryza, and conjunctivitis (the 3 C's) with Koplik spots preceding a face-to-body maculopapular rash is the classic measles clue.

Overview

A highly contagious viral exanthem, studied for its prodrome, pathognomonic Koplik spots, characteristic rash progression, and extreme transmissibility.

Classification

  • Viral exanthem syndrome
  • Measles morbillivirus (paramyxovirus)
  • Airborne, very high transmissibility
  • Vaccine-preventable

Lab & identification clues

  • Koplik spots on buccal mucosa vocabulary
  • Measles IgM serology concept
  • Rash begins at hairline/face then descends

Associations

  • Airborne spread with roughly 90% secondary attack in susceptibles
  • At-risk: unvaccinated, infants, malnourished
  • Complication vocabulary: pneumonia, encephalitis, SSPE
  • Vitamin A deficiency association

Commonly confused with

  • Rubella
  • Roseola (HHV-6)
  • Scarlet fever

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource