Autoimmune Flares and Blood Sugar Spikes: Understanding the Inflammation Connection

When most people think about high blood sugar, they picture sugary snacks or carb-heavy meals. But if you live with an autoimmune disease like lupus, Sjogren’s, or rheumatoid arthritis, your blood sugar can spike even if your diet is spotless.

Inflammation itself can push your glucose higher. This overlooked connection between the immune system and metabolic function can leave patients confused when their blood sugar rises despite clean eating and good habits. But once you understand what’s really going on, you can track flare-related glucose changes, reduce unnecessary worry, and advocate more effectively for your care.

The Science Behind Inflammation and Blood Sugar

When the immune system ramps up, it releases inflammatory cytokines like TNF-alpha and IL-6. These molecules interfere with how your cells respond to insulin, leading to temporary insulin resistance—even in people who’ve never had blood sugar issues before. Studies have shown that inflammation can reduce the effectiveness of insulin receptors, making it harder for glucose to move into cells where it's needed.

This insulin resistance isn’t always permanent, but during a flare, it can be powerful enough to cause measurable blood sugar spikes. This review from the National Institutes of Health offers a deeper dive into how inflammation alters metabolic function.

What Happens During an Autoimmune Flare

When your immune system launches an inflammatory response, your body sees it as an emergency. It releases stress hormones like cortisol to help deal with the perceived threat.

Cortisol does a lot of things, but one of its key roles is to raise blood sugar to make sure you have enough energy to fight the “attack.” In autoimmune disease, your body is attacking itself, so these stress hormones flood your system unnecessarily—and your blood sugar pays the price.

Even If You Don’t Have Diabetes

You might think this only matters if you’re already diabetic or prediabetic, but that’s not true. Over time, repeated inflammation-driven glucose spikes can increase your risk of insulin resistance, making future metabolic problems more likely. I use a Fitbit Charge 6 to help me predict flares and be prepared.

What to Watch For

If you have an autoimmune condition, you may notice patterns like:

• Higher fasting blood sugar after a flare

• Unexpected glucose spikes even when eating normally

• Increased carb cravings during or after a flare (your body wants quick energy to "fight")

Autoimmune Flares and the Hidden Stress Response

Inflammation doesn’t just trigger physical symptoms—it activates the same stress pathways your body uses for psychological distress. In other words, your body can’t tell the difference between a cytokine surge and an emotional crisis. Both send cortisol and adrenaline into overdrive.

Personally, I’ve noticed that if I’m flaring and I’ve also had a stressful week, my glucose becomes far less predictable. My body doesn’t always know the difference between grief and a virus. Either way, the result is a blood sugar spike.

Why It Matters

Chronic inflammation and unstable blood sugar create a feedback loop. High blood sugar fuels more inflammation, which triggers more hormonal stress, which pushes blood sugar higher—and the cycle repeats.

This matters because glucose variability—not just high blood sugar—has been linked to long-term complications, including nerve damage, vascular issues, and even cognitive changes. A 2023 report from the Mayo Clinic emphasizes that blood sugar swings, even in non-diabetics, can contribute to endothelial dysfunction and increased cardiovascular risk.

How to Break the Cycle

You don’t have to live in survival mode. These strategies can help interrupt the inflammation-blood sugar feedback loop and give your body room to heal. Each one is grounded in both research and personal experience.

• Track Your Patterns: Consider using a continuous glucose monitor (CGM) during flares to spot trends early. I personally use a CGM a few times a year—not continuously, but enough to understand my body's patterns. When I see a blood sugar spike coming with no food trigger, it’s often a sign that inflammation is ramping up even before I feel it.

• Prioritize Anti-Inflammatory Nutrition: Focus on whole foods, omega-3s, turmeric, leafy greens, and healthy fats. If you need help finding real-world meals that work on flare days, our sister blog Good Food, Real Life has an entire anti-inflammatory recipe section to inspire you.

• Manage Stress: Mindfulness, gentle movement, and even brief walks after meals can lower cortisol and stabilize blood sugar. When I'm flaring, I do 5-minute body scans or lie down with my legs elevated and music playing. It’s not dramatic, but it shifts my cortisol curve just enough to make a difference in how my body processes glucose.

• Stay Hydrated: Dehydration can worsen both inflammation and blood sugar swings. I aim for a full glass of water before each meal and sip throughout the day. When flaring, I switch to electrolytes—my favorite is Sugar-Free Liquid I.V. with a splash of lemon juice. It helps my body absorb what I’m giving it instead of letting it pass through uselessly.

• Work With Your Team: If you notice consistent glucose spikes during flares, talk to your rheumatologist and your endocrinologist (or primary care provider). This is a real metabolic phenomenon, and it deserves attention.

What to Say to Your Doctor

If you’ve tracked your blood sugar and noticed patterns around your flares, don’t brush it off—bring it up.

Here are a few phrases to help open the conversation:

• “I’m noticing elevated glucose readings after autoimmune flares, even when I eat clean. Could inflammation be affecting my metabolism?”

• “Would it be useful to try a temporary CGM to see how my body responds to flares?”

• “Can we explore how inflammation might be driving my insulin resistance?”

You’re not being dramatic—you’re being data-driven. Providers are increasingly aware of the inflammation-metabolism connection. Starting the conversation might lead to treatment changes that help both your immune system and your metabolic health.

What I Wish I Knew Sooner

When I first started tracking my blood sugar, I thought it would just help with fatigue and carb timing. I didn’t realize it would become one of the best flare-warning systems I had. Seeing numbers spike without dietary cause helped me connect the dots between inflammation and metabolism—and helped me speak more clearly with my care team.

If I could go back, I’d start tracking earlier. I’d be less afraid to bring up "borderline" numbers with my doctor. I’d trust myself when I felt something was off, even if labs hadn’t caught it yet. Because in chronic illness, patterns matter more than perfection.

The Bottom Line

Autoimmune flares don’t just affect your joints, skin, or energy—they impact your whole-body health, including your blood sugar. By learning how inflammation disrupts glucose metabolism, you can take more confident action to stabilize your numbers, reduce flare severity, and protect long-term metabolic health.

Want more real-world tools to help manage your autoimmune health? Visit our Ko-fi shop for symptom trackers, medication logs, and blood sugar-friendly meal planning resources built by patients, for patients.