From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history

A flare-up or flare or symptoms flare in myalgic encephalomyelitis/chronic fatigue syndrome is a temporary increase in symptoms, alternatively known as experiencing post-exertional malaise.[1][2] Some people use "crash" or "collapse" to refer to a flare.[3]

NHS definition[edit | edit source]


A worsening of symptoms, more than would be accounted for by normal day-to-day variation, that affects the person's ability to perform their usual activities. Flare‑ups may occur spontaneously or be triggered by another illness, overexertion or other triggers. Flare‑ups usually occur as part of post-exertional malaise but it is possible for other symptoms, such as pain, to flare-up without post-exertional malaise. The worsening of symptoms is transient and flare‑ups typically resolve after a few days, either spontaneously or in response to temporary changes in energy management or a change in treatment. A relapse lasts longer than a flare‑up.[1]

ME/CFS:diagnosis and management. NICE guideline (2021).

The UK's National Health Service definition of a flare-up can be found within the 2021 NICE guidelines.[1]

International Consensus Criteria[edit | edit source]

Symptoms flare is not a term defined in the ICC.[2]

Impact[edit | edit source]

Notable studies[edit | edit source]

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Learn more[edit | edit source]

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