Measles and rubella vs Roseola, erythema infectiosum, and hand-foot-mouth disease
How to tell Measles and rubella and Roseola, erythema infectiosum, and hand-foot-mouth disease apart when a board question makes them look alike.
Measles = 3 C plus Koplik; rubella = mild rash plus posterior nodes/congenital risk; roseola = fever then rash; fifth = slapped cheek; HFMD = mouth plus hands/feet.
Side by side
Measles causes cough, coryza, conjunctivitis, Koplik spots, high fever, and cephalocaudal morbilliform rash; rubella causes milder rash with postauricular/occipital nodes, and congenital rubella classically causes cataracts, sensorineural deafness, and PDA.
Roseola causes high fever then rash after defervescence; erythema infectiosum causes slapped-cheek rash from parvovirus B19, aplastic crisis in sickle cell disease, and nonimmune fetal hydrops; hand-foot-mouth causes oral ulcers plus hand/foot vesicles.
Measles and rubella are vaccine-preventable viral exanthems with major public health and pregnancy implications.
Roseola, parvovirus B19, and enteroviruses produce characteristic age/rash distributions that separate them from measles/rubella.
Koplik spots and 3 C symptoms support measles; posterior auricular nodes and congenital cataracts/deafness/PDA risk support rubella.
Rash after fever breaks supports roseola; slapped cheek and aplastic crisis risk support parvovirus B19; oral/hand/foot lesions support hand-foot-mouth.
The trap
All are childhood rashes, so the timing of fever and the mouth/face/node clues decide.
The repair move
For viral exanthems, anchor on the single signature clue before comparing rash color.
Try a free question
CoreAn unimmunized child has high fever, cough, coryza, conjunctivitis, Koplik spots, and a rash spreading from face downward. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Measles. The 3 C symptoms, Koplik spots, high fever, and cephalocaudal rash support measles.
Why the other choices are tempting
- B. Rubella is milder and has posterior auricular/occipital lymphadenopathy.
- C. Roseola has rash after fever resolves.
- D. Erythema infectiosum has slapped-cheek rash.
- E. Hand-foot-mouth has oral ulcers and hand/foot vesicles.
Flashcards
Tap a card to flip it.
What triad supports measles?
Cough, coryza, and conjunctivitis support measles.
What oral lesion supports measles?
Koplik spots on the buccal mucosa with cough, coryza, and conjunctivitis support measles.
Quick answers
What is the fastest way to tell Measles and rubella from Roseola, erythema infectiosum, and hand-foot-mouth disease?
Measles = 3 C plus Koplik; rubella = mild rash plus posterior nodes/congenital risk; roseola = fever then rash; fifth = slapped cheek; HFMD = mouth plus hands/feet.
What is the key clue for Measles and rubella?
Measles causes cough, coryza, conjunctivitis, Koplik spots, high fever, and cephalocaudal morbilliform rash; rubella causes milder rash with postauricular/occipital nodes, and congenital rubella classically causes cataracts, sensorineural deafness, and PDA.
What is the key clue for Roseola, erythema infectiosum, and hand-foot-mouth disease?
Roseola causes high fever then rash after defervescence; erythema infectiosum causes slapped-cheek rash from parvovirus B19, aplastic crisis in sickle cell disease, and nonimmune fetal hydrops; hand-foot-mouth causes oral ulcers plus hand/foot vesicles.
What is the common trap with Measles and rubella vs Roseola, erythema infectiosum, and hand-foot-mouth disease?
All are childhood rashes, so the timing of fever and the mouth/face/node clues decide.