Lupus Flare-Ups: Symptoms, Triggers and How Long They Last

What is a lupus flare-up?

A lupus flare, or flare-up, is when your lupus symptoms get worse and you feel ill as a result. [1] Lupus often comes and goes: periods when it is more active (flares) and periods when it settles (remission). [2] [3] NIAMS, part of the US National Institutes of Health, says flares can be mild or serious and are unpredictable. [3]

Doctors use a stricter definition: a measurable increase in disease activity in one or more organ systems, with new or worse signs, symptoms or test results, that is big enough to consider changing or increasing treatment. [1] In everyday terms, a flare is measured against your own usual, not against anyone else’s.

Many people notice the return of symptoms they have had before, but a flare can also bring new ones. [1] Some flares cause no clear symptoms and only show up in lab tests, which is one reason regular check-ups matter even when you feel well. [1] [5]

What are the signs and symptoms of a lupus flare?

The Lupus Foundation of America lists these as common symptoms of a flare: [1]

• More fatigue than usual
• Painful, swollen joints
• Rashes
• A fever that keeps going and is not caused by an infection
• Sores or ulcers in the mouth or nose
• General swelling in the legs

Other warning signs that a flare may be coming include pain, a tummy ache, a severe headache and dizziness. [4] [5] Lupus can also cause hair loss, swollen glands, chest pain when breathing in, and fingers and toes that turn white or blue in the cold (Raynaud’s). [2] [3] [7]

Lupus rash on the face. The best-known lupus rash is the malar or “butterfly” rash, which spreads across the nose and cheeks. [3] The NHS says lupus rashes usually come on after being in the sun. [2] Lupus can also cause round, scaly rashes anywhere on the body. [3] Because several kinds of rash can happen, the Lupus Foundation of America advises seeing a dermatologist who knows lupus about any new rash. [7]

Not every bad day is a flare. If your work or home life takes a lot of energy, it is normal to feel exhausted. [1] Your doctor will also want to rule out other causes of new symptoms, such as an infection or a side effect of medicine. [1]

What does a lupus flare feel like?

For most people, a flare feels like a louder version of their usual lupus. In a study of 101 women with lupus in Australia, the flare symptoms people reported most were joint and muscle pain (73%), fatigue (65%), a rash (30%) and headaches (24%). [12] Others described fevers, brain fog, shortness of breath, chest pain and dizzy spells. [12]

The fatigue is not ordinary tiredness. The NHS describes lupus fatigue as extreme tiredness that does not go away no matter how much you rest. [2] Lupus UK says almost 9 in 10 people with lupus report fatigue. [17]

The symptoms you had when you were first diagnosed often come back during flares. [7] Writing them down once, while you feel well, gives you a checklist to compare against when you start to feel off.

What causes lupus flare-ups?

No one knows exactly why lupus flares up or settles down. [2] But some triggers are well known, and they differ from person to person. [1] [5] [12]

In the Australian study, almost every woman could name at least one trigger for her own flares. About half named stress and about a third named sunlight. Some also named weather changes, overheating, lack of sleep and work. [12] These were people’s own reports, so treat any trigger as a pattern to check across several flares, not a proven cause. A flare is not your fault.

How long after sun exposure can a lupus flare start?

Often not straight away, which is why the sun is easy to miss as a trigger. In a study that shone UV light on small patches of skin, almost half of the people with lupus of the skin developed a lupus rash. On average the rash took about 8 days to start and about 12 days to fully develop. [9] Researchers have noted that people’s memory of being sun-sensitive often does not match test results, because of this delay between UV exposure and the rash. [10]

UV light can also bring on whole-body symptoms such as fatigue and joint pain, not only a rash. [8] [6] So when you look for a trigger, look back one to two weeks, not just at yesterday.

To protect yourself, the NHS advises sunscreen of at least factor 50 and a hat in the sun, and not sitting in direct sunlight or spending a lot of time in rooms with fluorescent lights. [2] The Lupus Foundation of America adds tightly woven clothing, sunglasses, UV-blocking window shades, and shields for fluorescent and halogen bulbs, and reapplying sunscreen every two hours. [8] In the UK, you can get sunscreen on prescription if you have lupus. [2]

How long does a lupus flare last?

There is no fixed length. The NHS says that when lupus flares up, symptoms become worse for a few weeks, sometimes longer, before they settle down again. [2] Some flares are short: the US Office on Women’s Health says you may have swelling and rashes one week and no symptoms the next. [5]

In the Australian study, women reported an average of about 7 separate flares over a year, adding up to about 30 flare days. The range was wide: some had no flares at all, and one had 240 flare days. [12]

Early treatment matters. Flares often have warning signs, and spotting them early and getting treatment quickly can make a flare less severe. [5] A flare that is getting worse, or affects your kidneys, heart, lungs or brain, needs your medical team, not waiting it out. [2] [5]

What helps during a lupus flare?

The main treatment for a flare comes from your rheumatologist, and it depends on which part of your body is affected. They may adjust your medicines: for example, starting or raising a steroid such as prednisone, or giving a steroid injection. [7] [5] Do not stop or change your lupus medicines on your own. [4]

Alongside that, these steps can help:

• Rest, and pace yourself so you do not get too tired [2]
• Ask family, friends and health professionals for help [2]
• Stay out of the sun and away from fluorescent and halogen light, and wear sunscreen and a hat outdoors [2] [5]
• Try relaxation techniques for stress, such as deep breathing [2] [4]
• Try to stay active, even on a bad day [2]
• Get enough sleep [5]

The Lupus Foundation of America suggests making a flare plan with your doctor before you need it: how to get seen quickly, whether you need blood and urine tests with every flare, and what they will do to bring your symptoms under control. [7] Its flare plan worksheet is free to download.

When should you call your rheumatologist about a flare?

The Lupus Foundation of America says to call your doctor right away if you think you are having a flare, if you notice new symptoms or your symptoms get worse, or if a new lupus medicine does not seem to be working. [14] Also call if medicine side effects are hard to manage, or if you have felt low for a while. [14]

A fever needs a doctor quickly. Lupus raises your risk of infections, and a fever can come from either, so the Lupus Foundation of America says to see a doctor straight away to find out which. [5] [7] Watch for signs that lupus is affecting your kidneys too: foamy pee, new swelling in your legs, feet, ankles or around your eyes, or high blood pressure. [13] [6] Kidney problems are common in lupus and are checked with urine and blood tests. [13]

What should you write down during a lupus flare?

NIAMS advises telling your doctor about symptoms that are no longer there, not only the ones you have on the day. [4] The Lupus Foundation of America suggests keeping a journal or notes app log of your symptoms and how you feel each day. [14] A short, dated record also makes it easier to spot your own triggers. These are the things worth noting:

If you like paper, our free printable trigger tracker keeps possible triggers and symptoms side by side, and the symptom tracker covers the day-to-day record. Our guide on how to track lupus triggers goes further into logging UV, weather and stress.

If writing it down is the hard part, Juno can take that job. You tell her what happened by voice or text, in your own words, and she adds it to your symptom timeline, with fatigue, joints and skin kept separate. Before an appointment, she turns months of notes into a summary for your rheumatologist. Juno’s lupus symptom tracker page shows how it works.

When is a lupus flare an emergency?

Lupus can affect the heart, lungs, kidneys and brain, so some symptoms need help straight away, whether or not you think they are part of a flare. [3] [14]

This article is for general information only and does not replace advice from your own clinician. Juno is a health assistant, not a medical provider.

Last updated 20 October 2026