flare up
US /fler ʌp/
UK /fler ʌp/
1.
to suddenly start burning more brightly or intensely
:
•
The campfire suddenly flared up, sending sparks into the night sky.
•
The dry brush flared up quickly in the strong winds.
2.
to suddenly become worse or more intense (especially of a disease or problem)
:
•
Her asthma tends to flare up during allergy season.
•
Old tensions between the two countries could flare up again.