Condition hub
Living with adult-onset still's
What Still's disease is, and why the ferritin number settles nothing.
Four things that turn up together
A fever spiking once or twice a day and dropping back to normal in between, a salmon-pink rash that comes and goes with the fever, sore joints, and a sore throat. That combination is what brings most people to a rheumatologist in the first place.
It is a diagnosis of exclusion
Infection and cancer have to be ruled out before this diagnosis gets made, which is why the work-up is long and why it can feel as though no decision is being reached. That waiting is the process working and not the process failing.
Ferritin rises, and proves nothing alone
It reaches some of the highest levels seen anywhere in medicine here, which is why it gets checked at all. The cut-offs different research groups have used range more than tenfold, so no single number can be quoted as the level that proves this illness.1
You can feel awful while the tests look quiet
People with this diagnosis scored worse than matched controls in every area of a quality of life survey, and that held even when the illness showed little or no sign of being active. Function, tiredness, pain and general health were all worse too.4
The four-step plan, applied to adult-onset Still's disease.
Get the right diagnosis
Fever, rash, joints and throat together, with infection and cancer ruled out first. Ferritin and glycosylated ferritin both get checked, and neither one has a cut-off that settles the question by itself.
Still's disease and labs →Clean up your food
No diet trial has been run in this illness, so any eating plan sold for it has cleared no bar at all. Eating well still does everything it does for anybody else, and a long steroid course makes that count for more.
Still's disease and diet →Detox your daily life
Smoking, workplace exposure and air pollution have never been measured in this illness. What is worth attending to instead is what a long corticosteroid course does to your bone, your blood sugar and your sleep.
Still's disease and environment →Build a stronger body
No exercise trial has ever been run in adult-onset Still's disease, so there is no program here to hand you. Build from what you can do now, and expect function to stay poor for a while after the disease goes quiet.
Still's disease and exercise →
Pro tip
If a ferritin number gets quoted at you as proof of this diagnosis, ask which cut-off it came from. Different research groups have used levels more than ten times apart and some used no fixed number at all, so the figure on its own settles the question in neither direction.
Ferritin, and what it doesn't settle
Ferritin is a protein that moves iron around the blood, and in this illness it rises to some of the highest levels seen anywhere in medicine. That's why your doctor checks it at all. The trouble is that the patient group and the comparison group overlap heavily, with plenty of controls at high values and plenty of patients lower down.
A second test called glycosylated ferritin usually gets ordered alongside, and it falls in this illness while total ferritin rises. Both tests have their own page here, explaining where their numbers came from and what the studies behind them did. Neither page prints a diagnostic cut-off, because there isn't one to print.
Macrophage activation syndrome
This is the most serious complication of Still's disease, and it happens when the immune system goes dangerously overactive, so catching it early counts for a great deal. Catching it in adults is harder than the published rules make it sound, because those rules were worked out in children with a related illness. The single ferritin rule inside them performs worst of all in adults.
The reason is built into the illness itself. Ferritin is already sky-high when Still's disease is active, so a cut-off designed to catch a further rise can't sort one from the other, and that is a limit of the rule rather than a failing of your team. The call rests on a doctor weighing several findings together instead of on any one number.
Living with it, and a finding that backs you up
Feeling unwell while your illness looks controlled is a written-down finding here rather than an impression. That deserves saying twice, because of what it corrects: you can feel much worse than your blood markers and joint counts suggest, and that is a known part of this illness. It isn't poor coping and it isn't exaggeration.
So say it plainly at your next visit. A good doctor will take it seriously when the bloods look fine, and a doctor who doesn't is missing something the research already shows. You're not asking anybody to take your word for it.
When to see a rheumatologist.
See a rheumatologist if you have:
- Daily spiking fevers, up to 102 degrees Fahrenheit or higher, lasting more than a week
- Transient salmon-pink rash that appears with fever and fades when temperature normalizes
- Sore throat at the onset of illness
- Joint pain or arthritis plus fever
- Lymphadenopathy and hepatosplenomegaly plus fever
- Negative infection and malignancy workups despite persistent symptoms
This gets diagnosed only after infection and cancer have been ruled out, so the work-up is long by design and a run of negative tests is part of it. A daily spiking fever with a rash that appears and fades alongside it is the combination worth bringing early.
References.
- Lee Y; Gyu Song G. Diagnostic accuracy of ferritin and glycosylated ferritin in adult-onset Still’s disease: a meta-analysis. Zeitschrift für Rheumatologie. 2025;84:234-240. 10.1007/s00393-025-01672-6Diagnostic accuracy meta-analysis of 8 studies
- Tada Y; Inokuchi S; Maruyama A et al. Are the 2016 EULAR/ACR/PRINTO classification criteria for macrophage activation syndrome applicable to patients with adult-onset Still’s disease?. Rheumatology International. 2018;39:97-104. 10.1007/s00296-018-4114-1Retrospective diagnostic accuracy study applying the 2016 sJIA MAS criteria to 76 adult-onset Still's disease patients
- Fautrel B; Le Moël G; Saint-Marcoux B et al. Diagnostic value of ferritin and glycosylated ferritin in adult onset Still's disease. The Journal of rheumatology. 2001;28:322-9. PMID 11246670Diagnostic accuracy study in adult-onset Still's disease versus a control group of patients with other conditions
- Ruscitti P; Rozza G; Di Muzio C et al. Assessment of health-related quality of life in patients with adult onset Still disease: Results from a multicentre cross-sectional study. Medicine. 2022;101:e29540. 10.1097/MD.0000000000029540Multicentre cross-sectional case-control study
- Javaux C; El-Jammal T; Neau P et al. Detection and Prediction of Macrophage Activation Syndrome in Still’s Disease. Journal of Clinical Medicine. 2021;11:206. 10.3390/jcm11010206Retrospective multicentre observational cohort of 206 patients with Still's disease
- Takken T; Van Brussel M; Engelbert R et al. Exercise therapy in juvenile idiopathic arthritis. Cochrane Database of Systematic Reviews. 2008;2010. 10.1002/14651858.CD005954.pub2Cochrane systematic review and meta-analysis of randomised controlled trials
This page gathers the published research on this subject into one place. The studies behind it were published between 1989 and 2026, and every figure links to the paper it came from. Those studies were peer reviewed. This summary of them was not. Dr. Sarah Luebker is reviewing these pages one at a time and has not reached this one yet, so it carries no medical review date and nothing here is her opinion or her advice to you. Each page gets updated as she reaches it. It is here in the meantime because the science is worth having in one organized place that is easy to find and easy to read. Talk to your own clinician before acting on any of it.