German measles vs epidemic roseola

German measles and epidemic roseola both are nouns.

Word	Noun	Adjective	Verb	Adverb
German measles	Yes	No	No	No
epidemic roseola	Yes	No	No	No

As nouns, German measles and epidemic roseola are synonyms defined as:

German measles and epidemic roseola: a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester

Other synonyms of German measles include rubella, three-day measles.

German measles (noun)	epidemic roseola (noun)
a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester	a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester