From Longman Dictionary of Contemporary Englishflare-upˈflare-up noun [countable] 1 ANGRYa situation in which someone suddenly becomes angry or violent Apart from one or two flare-ups the match went fairly smoothly.2 WORSEa situation in which someone suddenly has problems because of a disease or illness after not having any problems for a long time a flare-up of her arthritis
Examples from the Corpus
flare-up• She's following a low-fat diet, and hasn't had a flare-up in months.• When Labour returned to opposition after 1951, there was a flare-up inside the party.• In instances where a flare-up of the disease later attenuated earlier cosmetic benefits, patients became skeptical of surgery.• a flare-up in the dispute between Armenians and Azerbaijanis• They may move joints manually through the safe range of motion during acute flare-ups of arthritis.• I have had chronic low-back pain, with occasional flare-ups of worse pain, for at least five years. 