break open vs flare up

break open and flare up both are verbs.

Word	Noun	Adjective	Verb	Adverb
break open	No	No	Yes	No
flare up	No	No	Yes	No

As verbs, break open and flare up are synonyms defined as:

Other synonyms of break open include burst out, erupt, flare, irrupt.

break open (verb)	flare up (verb)
erupt or intensify suddenly	erupt or intensify suddenly
come open suddenly and violently, as if from internal pressure	ignite quickly and suddenly, especially after having died down
open with force