What’s New in Still’s Disease: Key Takeaways from EULAR 2025
At
EULAR 2025 in Barcelona, one of the most talked-about sessions focused on
“Big News in Still’s Disease Research You Need to Know”. For many patients, Still’s can feel overlooked compared to other autoimmune and autoinflammatory conditions, so this session felt especially meaningful. It delivered important updates about how Still’s is understood today, how it is diagnosed, and where research is heading.
Juvenile and adult Still’s are now understood as the same disease
One of the most significant updates is that systemic juvenile idiopathic arthritis (SJIA) and adult-onset Still’s disease (AOSD) are no longer being treated as separate conditions. While they differ by age of onset, current research shows they share the same underlying biology, immune pathways, and molecular signatures.
This is different from conditions like juvenile idiopathic arthritis and rheumatoid arthritis, which are now clearly defined as distinct diseases. In Still’s, the age of symptoms onset does not change the fundamental disease process. This shift matters because it allows research, treatments, and clinical trials to apply across age groups, helping patients of all ages benefit from the same scientific progress.
Tiffany and Eileen from AiArthritis report live from EULAR 2025 with exciting updates on Still’s disease—including new research, emerging terminology, and a surprise discovery announced for the first time during this session.
Still’s is increasingly seen as both autoinflammatory and autoimmune
Another major theme was how Still’s disease does not fit neatly into a single immune category. Researchers now describe it as a polygenic autoinflammatory disease, meaning multiple genes and immune pathways are involved.
Traditionally, autoinflammatory diseases affect the innate immune system, the part we are born with that responds quickly to threats like infection. Autoimmune diseases involve the adaptive immune system – which learns and adapts over time and is often influenced by environmental triggers.
Still’s appears to involve both sides of the immune system. This helps explain why it can look different from patient to patient and why it shares features with other autoimmune and autoinflammatory conditions. It also opens the door to new ways of thinking about treatment strategies.
IL-18 is emerging as a key biomarker
One of the most promising developments discussed was the role of interleukin-18, or IL-18. This inflammatory marker appears to be particularly elevated in Still’s disease and may help distinguish it from other autoimmune conditions.
Researchers are studying IL-18 not only as a diagnostic clue but also as a way to identify patients who may be at higher risk for serious complications like macrophage activation syndrome. Many people with Still’s are misdiagnosed early on with infections or viral illnesses, especially since some patients do not initially develop arthritis. A reliable biomarker like IL-18 could help shorten the time to diagnosis and improve early treatment decisions.
A new area of concern: Still’s lung disease
One of the most unexpected and important announcements was the introduction of a newly described condition being referred to as Still’s lung disease. This is a very new concept, and researchers emphasized that it is still early in the investigation process.
What is known so far is that some patients with Still’s develop a distinct type of lung involvement that does not fit neatly into existing categories. There is ongoing debate about possible risk factors, including whether certain biologic medications might play a role in triggering lung symptoms in a small subset of patients.
Some early data raised concerns about severe drug reactions that can affect the lungs, but other studies showed lung involvement occurring even in patients who were not exposed to those treatments. At this point, there is no clear cause, no established diagnostic criteria, and no reason for patients to panic. The key message is awareness. Researchers are paying attention, and AiArthritis will continue sharing updates as the science evolves.
Why this session mattered so much
This Still’s disease session was held in one of the largest auditoriums at the conference, a space typically reserved for the most impactful and forward-looking research. That alone sent a powerful message that Still’s disease is finally receiving the attention it deserves.
The discussion reflected a broader shift happening across rheumatology toward personalized medicine. Rather than viewing patients as one large group, researchers are focusing on subgroups, biomarkers, and individual disease patterns. For people living with Still’s, this means more targeted research,
better diagnostic tools, and greater hope for tailored treatments in the future.
The big picture for patients
While some of the science presented was complex, the takeaway for patients is encouraging. Researchers are refining how Still’s disease is defined, finding better ways to identify it earlier, and uncovering new aspects of the disease that could explain why symptoms vary so widely.
Most importantly, Still’s disease is no longer on the sidelines of research. It is firmly on the map, and the momentum seen at EULAR 2025 signals continued progress ahead.
As always, AiArthritis will keep translating these scientific advances into clear, practical information so patients and families can stay informed without feeling overwhelmed.
AiArthritis is the official host of Still’s Disease Awareness Day on September 7th. When the International Still’s Disease Foundation (ISDF) dissolved in 2017, they asked AiArthritis to house their remaining resources, which included becoming the host of Still’s Disease Awareness Day and managing the Still’s Disease Patient Support Group on Facebook. To learn more about Still’s Disease Awareness Day, visitthis link.
