Meaning of “break out” - Learner’s Dictionary

break out

phrasal verb with break uk us /breɪk/ verb (past tense broke, past participle broken)

B2 If a fire, war, disease, etc breaks out, it starts suddenly:

A fight broke out among the crowd.

to escape from prison:

to break out of jail
break out in a rash/sweat, etc

to suddenly have spots or sweat (= salty liquid) appear on your skin

(Definition of “break out” from the Cambridge Learner’s Dictionary © Cambridge University Press)