Adult-onset Still's disease

In medical terms the illness is autoinflammatory: instead of the body turning on one particular target, parts of the innate immune system, its first line of defence, switch on when they should not and flood the body with inflammatory messengers, interleukin-1 and interleukin-6 among them. Those messengers bring on the fevers, the rash and the inflamed joints.

Its trigger remains a mystery. An infection or some other stress may start the immune reaction in someone already prone to it, though no one cause has ever been pinned down. It is not passed down as an inherited disease, there is usually no family history, and it cannot be caught from someone else.

It is rare. Most often it starts somewhere between 16 and 35, though it can start at any age in adult life, and it affects women slightly more often than men. It is the adult form of the illness that in children is called systemic juvenile idiopathic arthritis, and international recommendations now treat the two as one disease, called Still's disease.

The hallmark is the combination of daily fevers, a passing rash and painful joints. You may notice:

• High fevers, often shooting up once or twice a day and usually dropping back in between
• A salmon-pink rash that may come out with the fever and fade as it falls
• Pain and swelling in the joints, and aching muscles
• Pain in the chest, when inflammation reaches the linings of the heart or the lungs
• Sore throat and swollen glands, and sometimes feeling generally ill

The inflamed linings around the heart and lungs (pericarditis and pleurisy, together called serositis) are a recognised part of the condition. Typically the pain is sharp and stabbing more than crushing, is made worse by breathing in or lying flat, and is relieved by sitting upright and leaning forward; it generally fades once the disease is under control. Even so, leave chest pain to a doctor to explain, since more serious causes can feel alike: chest pain that is crushing, tight or like a pressure, breathlessness that is severe, with gasping, choking or no breath to get words out, and palpitations that are going on now and do not settle, or that arrive with chest pain, breathlessness, faintness or a faint, are 999 or A&E emergencies, as the first list under When to seek help says, while new chest pain, new palpitations, or breathlessness that is new or getting worse, short of those, need an assessment the same day, from your GP, your rheumatology team or NHS 111. Our guide to inflammation and your heart says more about how inflammation can reach the heart.

Neither a blood test nor a scan can confirm the illness alone. Doctors reach the diagnosis from the typical combination of features, backed by blood tests that often show a great deal of inflammation and a very high level of ferritin, and, importantly, by ruling out infections, other inflammatory conditions and the other causes of a fever, some types of lymphoma among them. That is why a thorough specialist assessment matters so much.

Ultrasound can help to show inflammation when joints are involved. Point-of-care ultrasound is part of the consultation with Dr Borukhson, so a painful joint can usually be looked at on the same visit; if you want the detail, see what the ultrasound clinic page says about the scan.

In treating it, three things matter: calming the inflammation, getting the fevers and the joint symptoms under control, and keeping flares from coming back. Prednisolone or a similar steroid is often given to calm active disease, with methotrexate or another such medicine sometimes added so that the steroid can be cut down without a flare. When the disease persists or is severe, a biological medicine is used, such as anakinra, which blocks the action of a messenger called interleukin-1, or tocilizumab, which blocks the action of a messenger called interleukin-6, and either can work very well. International recommendations now favour starting one of these early so that the course of steroids can be kept short; on the NHS in England, anakinra is used for adult-onset Still's disease once two or more of the usual disease-modifying medicines have not controlled it.

These medicines need monitoring while you take them, and biological medicines and steroids can make infections likelier, so they are given under specialist care and explained to you fully before you start. The treatment is tailored to you and kept under review, and because the condition can wax and wane, ongoing specialist input is worth having. You and Dr Borukhson settle the plan together.

In a minority of people, adult-onset Still's disease tips the immune system into a runaway reaction called macrophage activation syndrome (MAS), which is one form of haemophagocytic lymphohistiocytosis (HLH). Though uncommon, it is life-threatening and is treated in hospital without delay; it may come at the very start of the illness or in a bad flare. It is one of the reasons close specialist follow-up matters so much.

A high fever that does not settle, in someone who also feels very unwell; bruising or bleeding easily; yellowing of the skin or eyes; or confusion or drowsiness that is new: any of these can be a warning sign of this complication, and each is a 999 or A&E emergency. Call 999 and do not drive yourself to A&E.

From day to day, the most help you can give yourself is to keep your specialist team up to date and to keep every review and blood test, since these watch over the illness and your treatment alike. Bring a short record of any fevers, rashes or flares in your joints to each appointment, so the treatment can be fine-tuned.

• Pace yourself during flares and rest while you have a fever, then build gentle activity back up as things settle
• Protect your bones by doing exercise that bears your weight, and if you take steroids, ask whether you need calcium and vitamin D
• Have your vaccinations when they are due, and talk to your team before a planned pregnancy or a new medicine

In most cases the outlook is good. About a third of people have a single bout that eases within a year, about a third have flares that come back, sometimes years apart, before the illness fades, and about a third have a longer-lasting arthritis, so your team keeps it under regular review.

Your regular reviews deal with most of what adult-onset Still's disease brings. Some signs cannot wait for one, and the lists below set them out with the 999 or A&E signs first; the paragraph below them says what can wait for a routine review.

Treat any of these as a 999 or A&E emergency: call 999 and do not drive yourself to A&E.

• Severe illness with suspected sepsis: a high fever with shaking, confusion, rapid breathing, or feeling dramatically worse over hours
• With a fever or feeling unwell, a rash that does not fade when you press it, a stiff neck with eyes that cannot bear bright light, or skin, lips or tongue turning blue, grey, pale or blotchy, since these can be signs of meningitis or sepsis, as can a very bad headache, confusion or a first seizure with a fever or feeling unwell; on black or brown skin the rash and the change of colour may be easier to see on the palms of the hands or the soles of the feet
• A high fever that does not settle, in someone who also feels very unwell; bruising or bleeding easily; yellowing of the skin or eyes; or confusion or drowsiness that is new, since these can be the signs of macrophage activation syndrome, an uncommon complication of Still's disease that threatens life
• Chest pain that is crushing, tight or like a pressure, that spreads to an arm, the jaw, the neck, the stomach or the back, that comes with breathlessness, sweating, feeling sick or feeling light-headed, or that came on suddenly and does not go away
• Breathlessness that is severe, with gasping, choking or no breath to get words out; or coughing up blood
• Palpitations happening now that do not stop, or that come with chest pain, breathlessness, feeling faint or fainting, since a heart whose muscle or rhythm is affected has to be checked at once
• Sudden severe pain in the abdomen or back, since the pancreas can react to prednisolone
• Lips, mouth, throat or tongue that suddenly swell, a throat that feels tight, very fast breathing or a struggle to breathe or to swallow, skin, tongue or lips turning blue, grey or pale (on black or brown skin this may be easier to see on the palms of the hands or the soles of the feet), becoming suddenly very confused, drowsy or dizzy, or fainting and not being able to be woken, since this can be a severe allergic reaction, anaphylaxis, which can follow a dose of any medicine
• An eye that suddenly and completely loses its sight
• Vomiting blood, or bleeding from the back passage that is heavy or will not stop, most of all with faintness, confusion or pain in the abdomen, or vomit that is black or dark brown, since a stomach ulcer on prednisolone can bleed
• Thoughts of harming yourself or ending your life, which steroids can bring on

Any of these needs an assessment that is urgent, on the same day, from your GP, your rheumatology team or NHS 111:

• A fever, or feeling generally unwell, on immunosuppressant, biologic or steroid treatment, since an infection has to be treated early; with Still's disease a fever may be the illness or an infection, and these medicines can mask or worsen an infection, so a doctor needs to tell the two apart that day
• A high temperature that is not getting better, or keeps coming back, before any treatment for Still's disease has started or after it has stopped, since its cause, an infection among the possibilities, has to be looked into that day
• A joint that is hot and swollen, with a fever or feeling unwell, since an infected joint has to be ruled out at once, at A&E or through NHS 111
• A joint that has become hot and very swollen suddenly, or is worsening quickly, even without a fever, since an infected joint does not always announce itself with one; a joint that will take no weight at all, or that cannot be moved, is a 999 or A&E emergency, whether or not there is a fever
• New chest pain, new palpitations, or breathlessness that is new or getting worse, since serositis, the illness's inflammation of the linings around the heart and the lungs, can bring them on, and the lungs themselves can be affected, so a cough that lingers should be checked the same day as well; palpitations happening now that do not stop, or that come with chest pain, breathlessness, feeling faint or fainting, belong to the first list
• A flare that is not settling on your usual treatment, or feeling rapidly more unwell, since the treatment may need changing quickly and the signs in the first list have to be watched for
• A new red, painful eye, or sight that has blurred, dimmed or changed, which needs an eye casualty or urgent eye clinic the same day, as does an eye that light hurts
• A marked change in mood or behaviour, confusion, or seeing or hearing things that are not there, on steroid treatment, since prednisolone can do this, the more so the higher the dose; confusion that is new or comes on suddenly is a 999 or A&E emergency, as the first list says
• Unusual thirst or hunger, or passing urine more often, on steroids, or swelling of the arms or legs, black or dark red stools, severe stomach pain, severe back pain, a severe upset stomach, being sick, or very bad dizziness or passing out, since each can be a steroid effect that needs checking without delay; pain in the abdomen or back that comes on suddenly and severely is a 999 or A&E emergency, as the first list says
• Contact with measles, chickenpox or shingles, since these infections can be severe on steroids and a medicine to protect you may be needed
• Being near someone with measles, chickenpox or shingles, while you take a medicine that weakens the immune system, since measles and chickenpox can be dangerous when the immune system is weakened, and you can catch chickenpox from someone with shingles if you have never had chickenpox; NHS 111 can tell you what to do that day

Short of the signs in the lists above, joint pain or swelling that is slowly coming back, or low-grade fevers that keep returning while you are off treatment, are for a routine review with your rheumatology team, which they can bring forward, so that treatment can change before a full flare builds; on treatment, a fever belongs in the second list. If you cannot tell how urgent something is, asking is never a mistake.

Spiking fevers with a rash and sore joints are a combination that always deserves a careful look, to find the cause and to rule out other serious illnesses. If that sounds like you, arrange a specialist assessment within days, through your GP or booked directly; a high temperature that is not getting better, or keeps coming back, needs your GP or NHS 111 the same day, as the second list under When to seek help says, unless it comes with the signs the first list gives a fever, which make it a 999 or A&E emergency.

How do doctors reach a diagnosis of adult-onset Still's disease?

The answer comes from the whole picture, not from one result. A specialist looks for the typical pattern of spiking fevers, a salmon-pink rash and joint symptoms, checks blood tests that usually show a great deal of inflammation, and, importantly, rules out infections and the other conditions that can look like it, which takes a specialist assessment. If your joints are affected, Dr Borukhson can examine them with point-of-care ultrasound at the same appointment for signs of inflammation.

Which treatments work, and does the illness ever burn out?

Treatment is meant to quieten the inflammation, bring the fevers and the joint symptoms under control and keep further flares away. Steroid tablets such as prednisolone often calm active disease within a short time, and methotrexate or a similar medicine may join them to hold the gains as the steroid is tapered. When the disease persists or is severe, a biological medicine that blocks one of the messengers driving the inflammation can work very well. Many people do well; for about a third the illness passes within a year, while for others it comes back in flares or lasts longer, which is why it is followed closely.

How does it differ from rheumatoid arthritis?

Each is an inflammatory condition that reaches the joints, but the two look different. Still's disease in adults tends to come with spiking fevers, a salmon-pink rash that does not last and a sore throat as well as the joint pain; rheumatoid arthritis is mainly a matter of joints that stay inflamed, without a daily fever or a rash. Blood tests and the ruling out of other causes also tell them apart, which is part of why a specialist assessment matters.

Can the heart or the lungs be involved?

Yes. The thin membranes that wrap the heart and the lungs can become inflamed (pericarditis and pleurisy, together called serositis), and less often the heart muscle or the lungs themselves. The pain of serositis is typically stabbing, unlike the crushing pain of a heart attack; deep breaths and lying flat tend to sharpen it, sitting upright and leaning forward to ease it, and it usually fades once the inflammation is treated. Chest pain is still not something to judge for yourself: chest pain that is crushing, tight or like a pressure, breathlessness that is severe, with gasping, choking or no breath to get words out, and palpitations you can feel right now that keep going, or that bring chest pain, breathlessness, faintness or a faint with them, are each a 999 or A&E emergency, as the first list under When to seek help says; short of those, new chest pain, new palpitations, or breathlessness that is new or getting worse need an assessment the same day, from your GP, your rheumatology team or NHS 111.

Which signs mean I need help urgently?

A high fever that does not settle, in someone who also feels very unwell; bruising or bleeding easily; yellowing of the skin or eyes; or confusion or drowsiness that is new: any of these can be a warning sign of macrophage activation syndrome, an uncommon but serious complication, and each is a 999 or A&E emergency, as are the rest of the signs in the first list under When to seek help. Call 999 and do not drive yourself to A&E. Short of the signs in the first list, chest pain, palpitations or breathlessness that has newly appeared or is worsening, a fever or feeling ill on immunosuppressant, biologic or steroid treatment, and a flare that is not settling on your usual treatment need an assessment the same day, from your GP, your rheumatology team or NHS 111, as does the rest of the second list under When to seek help. Close follow-up by your team helps to catch problems early.

Is a specialist needed?

Yes. When fevers keep returning together with a rash and painful joints, a thorough assessment is always needed, so that the true cause is found and other serious illnesses are ruled out. With no single test to confirm it, and a condition that can wax and wane and now and then bring complications, ongoing specialist care is worth having. A prompt specialist assessment, within days, through your GP or booked directly, lets the cause be found and the right treatment begin, fitted to you and adjusted over time; a high temperature that is not getting better, or keeps coming back, needs your GP or NHS 111 the same day, as the second list under When to seek help says, unless it comes with the signs the first list gives a fever, which make it a 999 or A&E emergency.