flare-up

noun

ˈfler-ˌəp 

1

: a sudden outburst or intensification

a flare-up of hostilities

2

: a sudden bursting (as of a smoldering fire) into flame or light

a danger of flare-ups

3

: a sudden appearance or worsening of the symptoms of a disease or condition

an asthmatic flare-up

Synonyms of flare-up

• flurry
• burst
• outburst
• outbreak
• flare

Examples of flare-up in a Sentence

took medication to prevent a flare-up of her asthma

there's no need for an angry flare-up, as we'll take care of the problem immediately

Recent Examples on the Web

Scientists’ best solar models presently struggle to precisely predict flare-ups on our own, most familiar star. —Joseph Howlett, Scientific American, 8 Apr. 2026

During Coulier's six-month checkup and PET scans, doctors discovered a flare-up had returned as an enlarged tumor. —Christina Dugan Ramirez, FOXNews.com, 6 Apr. 2026

Going gluten-free doesn't always help with IBS 🍞 Some people with irritable bowel syndrome (IBS) find that certain foods with gluten trigger flare-ups. —Abby Norman, Verywell Health, 6 Apr. 2026

That got a brief rise out of Heinen, but the flare-up quickly faded. —Aaron Portzline, New York Times, 3 Apr. 2026

Word History

First Known Use

1839, in the meaning defined at sense 1

Rhymes for flare-up

• buttercup
• backup
• blowup
• breakup
• buildup
• checkup
• cleanup
• holdup
• hookup
• lineup
• lockup
• makeup

Kids Definition

flare-up

noun

ˈfla(ə)r-ˌəp, 

ˈfle(ə)r-

: a sudden burst (as of flame or anger)

Medical Definition

flare-up

noun

-ˌəp 

: a sudden appearance or worsening of the symptoms of a disease or condition

an asthmatic flare-up