Quick answer: A true arthritis flare is a clear rise in symptoms above your usual level that lasts more than a day or two, often with more stiffness, swelling, warmth or tiredness. A bad day or pain spike usually settles within a day with rest and pacing. A hot, swollen joint with fever is not a usual flare and needs urgent help.
Arthritis symptoms go up and down. Some days are simply worse than others. So how do you know when it is a true flare that needs your flare plan, or a call to your rheumatology team, rather than a bad day that will settle by tomorrow? This guide helps you tell the difference, so you can respond in proportion: not ignoring a real flare, and not panicking over an ordinary dip.
Three things that can feel similar
| Pain spike | Bad day | True flare | |
|---|---|---|---|
| What it is | A short burst of extra pain, usually linked to a movement or task | A day of more pain or stiffness than usual, often after doing more or sleeping badly | A clear rise above your usual level of symptoms that lasts and affects daily life |
| How long | Minutes to hours | Usually a day | Usually several days or more |
| Typical clues | Eases with rest or changing position | Eases with rest, pacing and a good night | More stiffness, swelling, warmth, tiredness; may feel generally unwell |
| What to do | Pause, adjust, carry on gently | Pace, comfort steps, early night | Follow your flare plan; contact your team if not settling |
Arthritis UK (formerly Versus Arthritis) describes a flare as a period when symptoms become worse than usual, and notes that flares can last from days to weeks. The key words are "worse than usual" and "lasting". Knowing your own usual is therefore the starting point.
Step 1: know your baseline
Your baseline is what an ordinary day looks like for you. It might include some pain. Write down:
- Your typical pain score from 0 to 10
- How long morning stiffness usually lasts
- Which joints are usually affected, and whether any are normally swollen
- Your usual energy level
Without a baseline, every bad day can feel like a flare. With one, changes stand out. A pain tracking journal for two to four weeks is the easiest way to find yours.
Step 2: the five-question flare check
When symptoms rise, ask yourself:
- Is it clearly above my usual? For example, pain two or more points higher than your normal, or stiffness lasting much longer.
- Has it lasted more than a day or two? A bad day usually improves after a rest and a decent night's sleep. A flare tends to persist.
- Are there signs of inflammation? New or increased swelling, warmth, or tenderness of joints, especially in inflammatory arthritis.
- Is it affecting what I can do? Struggling with tasks you usually manage, such as dressing, cooking or work.
- Do I feel generally different? Much more tired, washed out, or slightly feverish, which can happen in inflammatory flares.
If you answer yes to the first two and at least one of the others, it is likely to be a flare. If you answer yes to only one, it is more likely to be a bad day. Either way, if you have any red flag signs (below), stop and get help.
Step 3: rule out red flags
Some symptoms are not a usual flare and need medical help:
- One joint that suddenly becomes hot, red, swollen and very painful, especially with fever or feeling unwell. This can be septic arthritis (joint infection), which the NHS treats as an emergency.
- Signs of infection while on immune-suppressing medicines, such as fever, chills, sore throat or a new cough.
- Symptoms you have never had before, such as a joint that has never been affected suddenly swelling.
- Back pain with numbness around the bottom or genitals, bladder or bowel problems, or weakness in both legs.
- Chest pain, breathlessness, signs of a stroke, or a new severe headache with jaw pain or vision change.
Our guide to red flag symptoms you should never ignore explains each in more detail.
What a flare looks like in different types of arthritis
Osteoarthritis
Osteoarthritis flares are often triggered by doing more than usual, such as a long walk, a day of decorating or gardening, or a minor twist or knock. The joint may ache more, feel stiffer, and sometimes swell. Stiffness after rest is typically short, though it may be a bit longer during a flare. Flares often settle over days to a few weeks with pacing, comfort measures and gentle exercise. The NHS notes that osteoarthritis symptoms can come and go.
Rheumatoid arthritis
Rheumatoid arthritis flares involve active inflammation. Common signs are more joints becoming swollen, warm and tender, longer morning stiffness, sometimes lasting hours, marked tiredness, and feeling generally unwell or "flu-ish". Flares can happen without an obvious trigger, or follow an infection, stress, or missed medicines. Because ongoing inflammation can damage joints, flares that do not settle should be discussed with your rheumatology team. NICE's rheumatoid arthritis guideline (NG100) supports rapid access to specialist advice and treatment adjustment during flares.
Psoriatic arthritis
Flares can include swollen joints, a whole swollen finger or toe, heel or tendon pain, back stiffness, and sometimes a skin flare at the same time. Tiredness is common.
Axial spondyloarthritis and ankylosing spondylitis
Flares usually mean more back and buttock pain and stiffness, often waking you in the second half of the night, with more tiredness. Pain typically improves with movement.
Gout
A gout attack is usually unmistakable: sudden, severe pain, often starting at night, in one joint, frequently the big toe, which becomes hot, swollen and red. The NHS says an untreated attack usually lasts 1 to 2 weeks, and prescribed treatment taken early should start to work within about 2 days. Because septic arthritis can look similar, get urgent advice if you feel unwell or have a fever, or if it is your first attack.
Fibromyalgia alongside arthritis
Many people have fibromyalgia as well as arthritis. Fibromyalgia flares involve widespread pain, tiredness, poor sleep and difficulty concentrating, but not joint swelling. Telling them apart matters, because inflammatory arthritis flares may need treatment changes, while fibromyalgia flares are usually managed with pacing, sleep and activity.
Common flare triggers
Flares sometimes have no clear cause. When they do, common triggers include:
- Overdoing it, especially after a good spell
- Infections such as colds, flu or urine infections
- Stress or emotional upset
- Poor sleep over several nights
- Missed, delayed or reduced doses of arthritis medicines
- A minor injury, twist or fall
- For gout, the NHS lists drinking too much alcohol, a very large meal, dehydration, an illness with a high temperature, a joint injury and some medicines
Looking back over your journal after a flare can help you spot your own triggers. Be cautious about blaming a single food or event unless the pattern repeats.
Step 4: what to do once you know
If it is a pain spike
- Stop or change what you were doing and change position
- Breathe slowly and wait a few minutes
- Carry on more gently, or break the task into smaller parts
If it is a bad day
- Pace your day: shorter tasks, more breaks, drop what can wait
- Use warmth for stiffness or cold for puffiness
- Keep gently moving, and get an early night
- Note it in your journal so you can see if it becomes a pattern
If it is a true flare
- Follow your written flare action plan if you have one
- Use the steps in our first 24 hours of a flare guide
- Use only medicines your clinician has agreed
- Contact your GP or rheumatology advice line if it is not settling within the time agreed with your team, if flares are becoming more frequent, or if you have inflammatory arthritis and more joints are swelling
Checking in over the following days
Sometimes you cannot tell on day one. That is fine. Use your comfort steps and check again on day two or three. These questions help:
| Check | Suggests it is settling | Suggests a flare that needs more |
|---|---|---|
| Pain score compared with day one | Lower, or back near your usual | Same or higher |
| Morning stiffness | Shorter than yesterday | Longer, or lasting hours |
| Swelling or warmth | None, or going down | Present and not improving, or new joints affected |
| Daily tasks | Getting easier | Still struggling with basics |
| Energy and how you feel | Improving | Exhausted, or feeling unwell |
If things are moving in the right direction, carry on pacing and build activity back up slowly. If they are not, follow your flare plan and contact your GP or rheumatology team as agreed.
Common mistakes when judging a flare
- Calling every bad day a flare, which can lead to over-resting and losing fitness.
- Ignoring repeated or long flares, which may mean treatment needs reviewing.
- Assuming a hot, swollen joint is "just a flare" when you feel feverish or unwell.
- Putting everything down to arthritis, when new symptoms could be something else.
- Changing medicines yourself, rather than contacting your team.
For carers: signs someone may be flaring
People do not always say when they are flaring. Signs include moving more slowly or stiffly, guarding a joint, needing more help than usual, being more tired, sleeping poorly, eating less, or being quieter or more irritable. For someone with dementia or communication difficulties, behaviour changes may be the main clue. If you notice these, ask gently, check for red flags, and use their flare plan if they have one.
When to get medical help
- Call NHS 111 or go to A&E for a suddenly hot, red, swollen joint with fever or feeling unwell.
- Call 999 for chest pain, severe breathlessness, signs of a stroke or collapse.
- Contact your GP or rheumatology team the same day if you have signs of infection on immune-suppressing medicines.
- Contact your GP or rheumatology team within a few days if a flare is not settling, more joints are swelling, or flares are more frequent or severe than before.
- Book a GP appointment if you have never been diagnosed and have swollen joints or long morning stiffness.
How long does an arthritis flare usually last?
It varies. Many flares last a few days, but some last weeks. Osteoarthritis flares often settle within days to a couple of weeks with pacing and comfort measures. An untreated gout attack usually lasts 1 to 2 weeks. If a flare lasts longer than your clinician has advised, contact them.
What are the first signs of a rheumatoid arthritis flare?
Common early signs include longer morning stiffness, joints becoming more swollen, warm or tender, and increased tiredness or feeling generally unwell. Some people notice they are struggling with grip or fine hand tasks. Contact your rheumatology team if these persist.
Can stress cause an arthritis flare?
Many people notice flares after stressful periods, and stress can make pain harder to cope with. Stress is not the only cause, and flares can happen without any trigger. Managing stress, sleep and pacing is still worthwhile.
Should I rest when I am having a flare?
A short rest for very painful joints is fine, but long periods of rest tend to increase stiffness and weakness. Gentle movement little and often, pacing and comfort measures usually work best. Avoid pushing through as if nothing has changed.
How can I tell a flare from a joint infection?
Joint infection usually affects one joint that suddenly becomes hot, red, swollen and very painful, often with fever, shivers or feeling unwell. It can be serious. If you have these signs, especially if you take immune-suppressing medicines, call NHS 111 or go to A&E rather than treating it as a flare.
Do I need to tell my rheumatology team about every flare?
Not necessarily about short, mild flares that settle with your plan. Tell them about flares that do not settle, involve more joints, keep coming back or need extra medicines. Ask your team how they would like you to report flares.
Sources and further reading
- Arthritis UK: Managing arthritis flare-ups
- NHS: Rheumatoid arthritis
- NHS: Osteoarthritis
- NHS: Gout
- NHS: Septic arthritis
- NICE NG100: Rheumatoid arthritis in adults
Educational information for people in the United Kingdom — not a diagnosis or personal medical advice. Charity no. 1218461. Pending clinical review. Everyone's situation is different, so always follow the advice of your own GP, pharmacist or rheumatology team. If you feel very unwell, call 999 or go to A&E. For urgent advice, contact NHS 111.
Continue with related help
- Flare action plan — free printable plan
- First 24 hours of a flare — what to do on day one
- Flare-up: the first 72 hours — days two and three
- Flare or frailty? — for older adults
- Red flag symptoms — when it is not a flare
- Pacing — avoid boom and bust