flare up

v.- encender | exacerbar | empeorar | agravars.- exacerbación | empeoramiento | estallido

encenderse, encolerizarse, estallar

(n.) = recrudecimiento
Ex: He demonstrates how the plague came to be dealt with by both the French and the Africans between its first manifestation in 1914 and its final flare-up in 1944 and 1945.

(v.) = recrudecer, empeorar, agravarse
Ex: There will always be conflicts that flare up suddenly and call for a rapid response.