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Glossary

Flare

A stretch when your disease gets more active than usual. Sometimes a score picks it up, and sometimes only the person having it can describe it.

Fear of causing a flare is one of the main reasons people with autoimmune disease avoid exercise. Several trials counted the flares that happened. The counts came back zero.

Quick answerA flare is a rise in disease activity above your usual level, and the research definitions differ from one disease to the next. The most useful evidence here is about exercise. A Cochrane review pooled 13 randomized trials in lupus and recorded zero flares and zero serious harm.
Zero flares across 13 trials is a strong safety signal, and it still isn't a promise about you. Trial patients get picked, they get supervised, and their disease is usually stable, and the Sjogren trial that reported no flares had recruited women who never exercised into supervised walking. So what this evidence undoes is the idea that exercise is risky by nature in these illnesses. One more thing is worth saying: this site holds no source on what does set off a flare, so this page can't give you a trigger list and it won't invent one.

What the word means, and how loosely

A flare is a stretch when your disease gets more active than usual, and that definition is vague because the vagueness is real rather than a dodge. Research definitions differ by disease and by study, where some use a change in a combined score, some use a doctor's judgment, and some use whether the treatment had to be stepped up. There isn't one agreed line.

This site holds no source comparing those definitions, so which one your rheumatology team works from is a question only they can answer. Asking is fair, and the answer decides what they want you to mention and when. A person and a protocol can mean quite different things by one word.

What all the definitions share is that they describe activity rather than experience, which is the same split that makes remission a measurement rather than a feeling. Somebody can feel dreadful without meeting any flare definition. The reverse happens too.

Why a bad week isn't automatically a flare

Feeling terrible fits perfectly well with a controlled disease, which is one of the more disorienting features of these illnesses. One study asked 313 adults with inflammatory arthritis about their sleep, where the disease was mostly quiet or nearly quiet, and 63.7 percent with rheumatoid arthritis still slept badly. In psoriatic arthritis it was 61.5 percent and in axial spondyloarthritis 66.7 percent, so about two in three people with a controlled disease were sleeping badly.

That study looked at people at one moment, so it describes symptoms appearing alongside controlled disease rather than showing one causing the other. What it does argue is that a string of bad days needs mentioning rather than interpreting. Telling a flare from everything else is a call your team is better placed to make than you are, and they need your symptoms to make it.

The reverse mistake costs more than this one does. Write off rising symptoms as a bad week and you delay a response you may need. Three things produce the identical feeling, which are an infection, a missed or reduced dose, and plain variation in the illness, so changing your own medication before that conversation throws away the information needed to tell them apart.

Common misconceptions.

Myth. Exercise will trigger a flare.

Reality. The trials that counted them say otherwise. A Cochrane review pooled 13 randomized trials of exercise in lupus and recorded zero flares and zero serious harm, and a 16-week walking trial in Sjogren syndrome reported the same. Those patients were supervised and their disease was mostly stable, so this isn't a guarantee for every situation. It does move the burden of proof, though, and the claim that exercise is risky now has to earn its keep.

Myth. A flare means my treatment has failed.

Reality. It means your disease activity rose, and that can happen for reasons that have nothing to do with a drug wearing off. An infection can do it, a missed dose can do it, and so can plain variation in the illness. So a flare should start a conversation with your team rather than a change you make alone, because the right response depends on which of those explanations fits you.

Myth. I can tell a flare from a bad week.

Reality. Sometimes, and the two overlap more than most people expect. About two in three adults with inflammatory arthritis slept badly even when their disease was quiet, so feeling terrible fits perfectly well with a controlled score. That's a reason to mention your symptoms rather than diagnose yourself, in either direction, because the answer changes what should be done about it.

Myth. Managing stress will stop my flares.

Reality. One randomized trial tested that, giving talking therapy to lupus patients under high daily stress and watching both flares and immune measures. The therapy did improve their mood scores and their quality of life. Its authors say they found no real change in any immune measure at all, so stress work is worth having for what it does deliver, and this trial doesn't back it as a way to stop flares.

Related terms.

References.

  1. Frade S; O'Neill S; Greene D et al. Exercise as adjunctive therapy for systemic lupus erythematosus. The Cochrane database of systematic reviews. 2023;4:CD014816. 10.1002/14651858.CD014816.pub2Cochrane SR
  2. Miyamoto S; Valim V; Carletti L et al. Supervised walking improves cardiorespiratory fitness, exercise tolerance, and fatigue in women with primary Sjögren’s syndrome: a randomized-controlled trial. Rheumatology International. 2019;39:227-238. 10.1007/s00296-018-4213-zRandomised controlled trial
  3. Navarrete-Navarrete N; Peralta-Ramírez M; Sabio-Sánchez J et al. Efficacy of Cognitive Behavioural Therapy for the Treatment of Chronic Stress in Patients with Lupus Erythematosus: A Randomized Controlled Trial. Psychotherapy and Psychosomatics. 2010;79:107-115. 10.1159/000276370Randomised controlled trial
  4. Polak D; Kolasińska M; Wilk M et al. Sleep disorders in RA, axSpA and PsA are common despite good disease activity control—direct comparison of sleep quality and its risk factors using MDHAQ and PSQI. Clinical Rheumatology. 2026;45:957-965. 10.1007/s10067-025-07892-0Cross-sectional study of 313 adults from the PolNorRHEUMA registry: RA n = 129

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This page gathers the published research on this subject into one place. The studies behind it were published between 1989 and 2026, and every figure links to the paper it came from. Those studies were peer reviewed. This summary of them was not. Dr. Sarah Luebker is reviewing these pages one at a time and has not reached this one yet, so it carries no medical review date and nothing here is her opinion or her advice to you. Each page gets updated as she reaches it. It is here in the meantime because the science is worth having in one organized place that is easy to find and easy to read. Talk to your own clinician before acting on any of it.