Juvenile idiopathic arthritis (JIA)

In JIA the immune system, which is there to protect the body, attacks the lining of the joints and inflames it: it is an autoimmune condition. Why it does so is still not fully known, and for most children no single cause is ever found. The present thinking is that genes, many of them ones that steer how the immune system behaves, make some children susceptible, and that something in the environment, an infection for example, then starts the process off. It is not passed down in any simple way, and nothing you or your parents did or failed to do brought it on.

JIA starts before the 16th birthday by definition. Most types are commoner in girls, whereas enthesitis-related arthritis mostly affects boys, often older ones, much as the matching conditions in adults do.

JIA is a family of conditions that behave in different ways, not one disease. It is divided into types, and most of them have a counterpart among the conditions seen in adults:

• Oligoarticular JIA involves no more than four joints. It is the most frequent type, and the type in which uveitis, the inflammation inside the eye, turns up most often.
• Polyarticular JIA reaches five joints or more; when rheumatoid factor is present, it behaves much like adult rheumatoid arthritis.
• Systemic JIA brings fevers and a rash with the arthritis; it is Still's disease in childhood, and international recommendations now treat adult-onset Still's disease as the same illness starting later.
• Enthesitis-related arthritis (ERA) centres on enthesitis, inflammation where tendons fix to bone, and in adult life it overlaps with axial spondyloarthritis.
• Psoriatic JIA goes with psoriasis, and its adult counterpart is psoriatic arthritis.
• Undifferentiated JIA is the label used when the features do not fit any one of the other types.

An adult with a history of JIA usually comes to a rheumatologist for one of two reasons.

Arthritis that is active now. JIA is not something everyone grows out of. In a large share of people it stays active after childhood and goes on needing treatment, and the diagnosis stays JIA however old you are. Stopping treatment or slipping out of follow-up at this point can let the disease flare unchecked and do more damage, which is why continuing specialist care counts.

What the early years left behind. Even once JIA has gone quiet, inflammation in childhood and adolescence can leave its mark: joints that are damaged or misshapen, osteoarthritis arriving early in joints the inflammation damaged, movement that is limited, a limb or the jaw that grew differently, and thinner bones. Much depends on separating old damage that has settled from inflammation that is active now, since the two are handled quite differently.

The starting point is to weigh up how much of what you notice now comes from active inflammation and how much from damage done in the past, since each calls for its own approach. To tell them apart, your rheumatologist takes your history (which type of JIA you have, what treatment you have had, and whether the eyes have been involved), examines you, and arranges blood tests for inflammation and antibodies, with imaging.

Ultrasound earns its place here, since it can show whether a joint or a tendon is inflamed today or simply carries old damage. Point-of-care ultrasound is part of the consultation with Dr Borukhson, so that question can often be answered at the first appointment. For what the scan involves, see the ultrasound clinic page.

Arthritis that is still active is treated much as its adult counterpart would be, with disease-modifying medicines (DMARDs), methotrexate for example, and with biological medicines where needed, to quieten the inflammation and protect the joints. A specialist prescribes them and arranges the blood tests and checks they need, and steroids, given for a short spell or as an injection into a joint, can help to settle a flare.

When the main problem is damage, not inflammation, the emphasis moves to keeping you moving and comfortable: physiotherapy and protecting the joints, treating the osteoarthritis that can follow, looking after your bone health, and, for a joint that is badly damaged, referral in good time for a surgeon's opinion. Where the balance lies is personal to you. You and Dr Borukhson settle the plan together.

Keeping active is among the most valuable things you can do. Regular exercise that is gentle on the joints keeps them moving and the muscles around them strong, and a healthy weight takes strain off them. Not smoking is good for the inflammation and for the bones alike, and bone strength deserves attention after arthritis in childhood and any steroid treatment; our guide to osteoporosis explains why.

Keep to the eye checks your team arranges, because in some types the inflammation inside the eye can be silent, and tell your team about any trouble with your jaw, since its growth can be affected. On medicines that damp down the immune system, stay up to date with vaccinations and plan ahead before a pregnancy.

Most people with JIA live a long and full life, and regular contact with a specialist helps to keep it that way.

For an adult with JIA, most problems can wait for a planned appointment. Nothing in the lists below can wait; they run from the most serious down, and the paragraph below them deals with the rest.

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 systemic JIA, the childhood form 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
• 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

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; a fever on such treatment should not be blamed on the arthritis until a doctor has checked it
• 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 systemic JIA can bring inflammation around the heart and lungs (serositis), and on methotrexate chest pain or breathlessness can, rarely, be a sign of inflamed lungs, as can a cough that persists, which needs the same-day check too; palpitations happening now that do not stop, or that come with chest pain, breathlessness, feeling faint or fainting, belong to the first list
• 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, since JIA can bring on uveitis, which can threaten the sight if it is not treated and may have been present for a while without any symptoms; our uveitis guide explains the condition
• 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, a flare that refuses to settle, with several joints hot, puffy and stiff, is for your rheumatology team or GP to see within days. Fevers that return with a rash can mean that systemic JIA, the childhood form of Still's disease, has woken up. With it can come macrophage activation syndrome, a complication our guide to adult-onset Still's disease describes; its signs are a 999 or A&E emergency, as the first list says. On treatment that lowers your defences against infection, a fever is for the same-day list; off it, a high temperature that is not getting better, or keeps coming back, is for your GP or NHS 111 the same day, and other fevers with a rash are for your team or GP within days. If enthesitis-related JIA has reached your spine, read what our axial spondyloarthritis guide says about the back's warning signs. Changes that creep on slowly, such as stiffness that builds over weeks, a joint that aches more than it did, or one that has started to catch, are for a routine appointment with your team or GP. If you cannot tell how urgent something is, asking is never a mistake.

JIA stays with you for life, so specialist care that carries on into adulthood is important. Many young people lose touch with specialist care after leaving children's services, and that can let active disease flare unseen or complications go unchecked. Some types also bring a risk of inflammation inside the eye (uveitis) that gives no warning, and the long-term effects of the condition and of past treatment, on the bones among other things, deserve regular review. Anyone who had arthritis in childhood or adolescence, active now or not, can have a specialist look at where things stand and arrange suitable follow-up and treatment, through a GP or booked directly.

My JIA began in childhood. Does an adult rheumatologist still need to see me?

Often, yes. JIA stays your diagnosis for life, and for many people the arthritis is still active after childhood, or has left damage that needs looking after. Where it appears to have gone quiet, a specialist can confirm whether inflammation lingers, look out for complications and make sure the care you need is in place. Dropping out of follow-up after leaving children's services happens often, and it is worth avoiding.

Can arthritis in childhood leave lasting effects?

It can. Inflammation in childhood and the teenage years can damage joints for good, bring on osteoarthritis early in the joints it damaged, limit movement, make one limb or the jaw grow differently, and thin the bones. An adult rheumatologist sorts out which part of the picture is past damage and which is inflammation that is active now, since each needs a different approach.

Is adult JIA just rheumatoid arthritis by another name?

No, although some forms look much like it. JIA is a family of conditions that start in childhood, and several of its types match conditions met in adults: the form with rheumatoid factor is close to adult rheumatoid arthritis, enthesitis-related arthritis overlaps with axial spondyloarthritis, and the psoriatic form mirrors psoriatic arthritis. The diagnosis stays JIA after you turn 18, and the type guides the treatment.

After years of calm, can JIA become active again?

Yes. It can lie quiet for years and then flare, which is one reason to stay in touch with a specialist even when things are going well. If it does, the flare is looked at like any fresh inflammation, through an examination, blood tests and an ultrasound scan where useful, and the treatment is adjusted until it settles.