Flare-up (noun)

1. A sudden increase in intensity or sudden outbreak, especially of a disease, fire or conflict.
2. A sudden burst of intense activity or emotion.

Origin:

From middle english, fleren, to shine, from old english, flǣran, to shine, glitter; akin to old high german, flāren, to shine, gleam.

Examples:

1. There was a flare-up of the conflict in the Middle East.
2. The fire department was called to put out the flare-up in the building.
3. The patient's condition worsened with a sudden flare-up of their symptoms.
4. There was a flare-up of anger when the proposal was rejected.
5. The economy experienced a short-lived flare-up in growth.