rosacea vs acne

rosacea and acne both are nouns.

Word	Noun	Adjective	Verb	Adverb
rosacea	Yes	No	No	No
acne	Yes	No	No	No

As nouns, acne is a hypernym of rosacea; that is, acne is a word with a broader meaning than rosacea:

rosacea: a skin disease of adults (more often women) in which blood vessels of the face enlarge resulting in a flushed appearance
acne: an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones

rosacea (noun)	acne (noun)
a skin disease of adults (more often women) in which blood vessels of the face enlarge resulting in a flushed appearance	an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones