What Is a Flare, Really?
The word "flare" gets used constantly in autoimmune communities, but it rarely gets a clear definition. If you've been told your disease is flaring, or if you suspect one is starting, understanding what's actually happening in your body can help you respond more effectively and communicate more clearly with your care team.
A flare is a period of increased disease activity following a period of relative stability or remission. In practical terms, it means your immune system has ramped up its misdirected attack on your own tissues, and your symptoms are worsening as a result. Flares vary widely depending on the condition. A lupus flare might bring joint pain, fatigue, and a rash, while a multiple sclerosis relapse could involve new or returning neurological symptoms.
Recognizing a Flare
One of the tricky parts of flare recognition is that many autoimmune symptoms also appear in everyday life. Fatigue, joint stiffness, and brain fog can have a dozen causes, from poor sleep to a virus to stress. What distinguishes a flare is usually the pattern: symptoms that are familiar to you, returning with intensity, often across multiple body systems at once.
Keeping a symptom journal, even a simple one, can make a significant difference. Noting your pain levels, energy, sleep quality, and any new symptoms on a scale of 1 to 10 gives you a baseline to compare against. When things shift noticeably from your personal normal, that pattern becomes evidence you can bring to your doctor.
What Triggers a Flare?
Research points to several common flare triggers, though they vary by condition and by person. Infections are among the most well-documented, since fighting off a pathogen can activate the same immune pathways that drive autoimmune activity. Other frequently reported triggers include physical or emotional stress, sun exposure (particularly relevant in lupus), disrupted sleep, certain medications, and hormonal changes.
Not every flare has an identifiable cause, and it's important not to blame yourself when one occurs. Your immune system is responding to its own internal signals that are not entirely within your control.
Communicating with Your Care Team
When you contact your doctor about a possible flare, specific language helps. Rather than "I feel worse," try describing which symptoms have changed, how long they've been present, and how they compare to your baseline. If you track symptoms, bring that data.
Ask your care team ahead of time what their protocol is for flares. Some conditions have established step-up treatment plans, and knowing yours in advance means you're not scrambling when symptoms spike. It's also worth clarifying when a flare warrants an urgent call versus a scheduled appointment, since the answer differs by condition and severity.
Apps That Can Help You Track
If a paper journal isn't your style, several apps are designed specifically to support people with chronic and autoimmune conditions. Folia Health is free and lets you log symptoms, medications, flares, and other daily factors in one place. Bearable was built by people with chronic illness and is highly customizable, covering pain, fatigue, mood, sleep, and medication in a single dashboard.
Mymee pairs an app with a health coach to help identify personal triggers over time, though it operates as a subscription program rather than a standalone tool.
The American Autoimmune Related Diseases Association also maintains a curated list of patient apps that is regularly updated and worth bookmarking. Whatever tool you choose, the goal is the same: to arrive at your next appointment with data, not just a feeling.
This article is for general informational purposes only and does not constitute medical advice, diagnosis, or treatment. The content here is not a substitute for professional medical advice from a qualified healthcare provider. Always consult your physician or specialist before making any changes to your treatment or care plan. If you believe you are experiencing a medical emergency, call 911 or your local emergency number immediately.