We really appreciate the time our presenters have spent compiling answers to these Top 10 questions. These were selected from the many submitted and covered at our Information Day in July last year (2025), which was hosted with the OPTIMAL Centre of Research Excellence and the Murdoch Children’s Research Institute.
How is KD diagnosed?
Kawasaki disease (KD) is a clinical diagnosis; there is no specific diagnostic test. The diagnosis is made by a child having a prolonged fever of 4 or more days together with 4 or 5 well-recognised clinical diagnostic features. These features are (i) skin rash; (ii) conjunctival inflammation (redness of the eyes); (iii) changes to the mouth and throat (red lips, strawberry tongue, red throat); (iv) redness and swelling of the hands and feet; peeling of the skin around the nails later in the illness; and (v) enlarged lymph nodes (glands) in the neck.
These features come on sequentially over a number of days and often are not all present at the same time. In some children, especially infants, the diagnosis can be made even if there are less than 4 clinical features present. In these cases, blood and other tests may provide additional information, particularly if they show high levels of inflammation and exclude other causes for fever. About one third of children with KD will also have another infection, such as a viral infection at the same time.
The diagnosis of KD can be difficult and may therefore take some time while other causes are excluded.
If KD is diagnosed, then an ultrasound of the heart and coronary arteries (echocardiogram or echo) is performed. However, an echo is not usually used as a diagnostic test as it is normal in three quarters of children with untreated KD.
What causes KD? Is there a genetic basis or link to having vaccines?
The cause of KD has been one of the enduring mysteries of paediatrics; we still are not sure what causes it.
However, it is generally agreed that KD results from more than type of common infection triggering abnormal inflammatory responses by the child’s immune system. This only happens in a minority of children and there is good evidence that some children are genetically more likely to develop KD if they come across the infectious triggers for KD.
There has been lots of research to identify a specific infection as the cause of KD (including COVID-19), but this has been negative. Also, efforts to identify non-infectious triggers, such as vaccines or chemicals, have not shown any link with KD.
KD is not contagious to other children. The risk of KD in siblings of children with KD, although modestly increased, is still low. It is important to remember that KD is a relatively uncommon condition; there is one new case diagnosed each day in Australia.
Is KD painful?
What are the symptoms?
Children with KD are frequently described as being “irritable” which means that they are upset and difficult to settle. This is probably a combination of the high fever and some of the symptoms which are likely to be painful. The most common symptoms such as conjunctivitis (red eyes), mucositis (red lips), lymphadenopathy (swollen lymph glands) or red swollen hands are all caused by inflammation which is an immune process known to be associated with pain. It is difficult to tell if the skin rash is painful for children with KD.
Less commonly, children have inflammation in other areas such as their joints causing arthritis (joint pain), the external lining of their brains (sometimes called aseptic meningitis as it is not caused by infection but more an inflammatory reaction) which can cause headache. Other complications of KD, including gall bladder swelling and blockage (hydrops of the gall bladder), may also cause pain in the initial stages.
The good news is that the inflammatory changes are very responsive to standard treatments for KD and usually will settle quickly providing symptomatic relief for children with KD.
The coronary artery changes are not thought to cause pain unless the blood supply to the heart is reduced and the blood supply to the heart muscle is reduced but this is a very rare complication.
What is IVIg, where does it come from and why is it used in KD?
Immunoglobulins are antibodies, and part of the immune system. In health, their main role is to help fight infections.
Immunoglobulins are collected from plasma – the liquid part of the blood – donated by blood donors.
Immunoglobulins can be used for treatment of a wide range of conditions. In some people with low immunoglobulin levels, replacing immunoglobulins to normal levels can reduce the risk of infection. These treatments may be administered either intravenously (through a vein) or subcutaneously (under the skin).
High-dose intravenous immunoglobulins (IVIg) can also be effective treatment for many other conditions, including some with inflammatory, immune, or infectious causes, or where the underlying cause is not known.
Kawasaki Disease is one of these conditions and IVIg is a mainstay of current therapy. Under the National Blood Authority Criteria, treatment of KD is approved for access to government-funded immunoglobulin therapy, at no direct charge to the patient.
Currently there is no synthetic (artificial) alternative to plasma-derived IVIg, and thousands of plasma donations need to be processed to make one batch. Clinical demand is growing, and Australia now imports over half the immunoglobulins we use. IVIg products are also very costly, in part reflecting the many steps required for their production and to make sure they are as safe as possible. These include careful blood donor selection, testing of donated plasma, treatment of the plasma and the final product during preparation to reduce infectious and other risks, and careful documentation of all steps in the process.
Ongoing supply of plasma is essential to make sure that there is enough IVIg for patients who need it. In Australia, you can check if you are eligible to donate plasma at: https://www.lifeblood.com.au/donors/blood-plasma-platelets/making-a-donation
More information on how immunoglobulins are managed in Australia is available here:
https://www.blood.gov.au/immunoglobulin-therapy
and a useful video is available here:
https://www.blood.gov.au/immunoglobulin-videos-clinicians-and-patientsWhat are the risks/rate of re-occurrence and needing another round of treatment?
After the first treatment with intravenous immunoglobulin (IVIg), about one-third of children may need additional treatment in the following days to weeks to fully settle that episode of KD. This may include a second dose of IVIg or other medicines to help reduce inflammation and support recovery.
Once that episode of KD has completely resolved, the chance of a child developing KD again is very low. Studies show that only a small number of children (less than 2%) ever experience a second episode.
If a child has recovered from KD and their heart is normal, are there any other health problems they might face later in life, like autoimmune conditions?
If a child was appropriately treated with timely IVIg, had no coronary artery involvement, and inflammation fully resolved, most children will not experience ongoing problems related to KD.
KD does not appear to significantly increase the lifetime risk for other autoimmune conditions (such as lupus, rheumatoid arthritis, inflammatory bowel disease or multiple sclerosis). Large follow-up studies have not shown a consistent or strong association, and the immune system changes have not been shown to result in clinically meaningful disease if no recurrent or chronic inflammation occurs.
Children who fully recover typically have normal immune function after resolution and do not have higher rates of infections, allergies or chronic inflammatory conditions. If ongoing inflammation or recurrent KD episodes occur, re-evaluation with a specialist including counselling may help you understand these issues specifically for your child and family.
For all children whose echocardiograms (an ultrasound scan that shows how the heart muscle and heart vessels are working) are normal during and after KD, long-term cardiovascular outcomes are considered similar to the general population.
As clinicians, we would recommend that children and families take a proactive approach to long-term cardiovascular health and wellbeing to improve lifelong cardiometabolic risk. This includes heart-healthy habits including regular exercise, balanced diet, avoiding smoking and vaping, screening and management for diabetes and high blood pressure, manage cholesterol levels, avoid alcohol consumption and maintaining a healthy weight.
If, however, there was evidence of during or after KD of coronary artery dilatation (widening), aneurysms (see question 7) or heart dysfunction, children are considered to be at an increased lifetime risk of heart complications and the advice of your local cardiologist should be followed.What are the long-term outcomes for children with aneurysms?
Kawasaki disease causes inflammation of the blood vessels (vasculitis). In some children, this can affect the heart’s blood vessels (coronary arteries) and lead to areas where the vessel becomes wider, called aneurysms. Over time, these areas can change – the vessel wall may become thicker or harder and blood flow may not be as smooth. Because of these changes, there can be a higher chance of blood clots forming in the coronary arteries, leading to a myocardial infarction (heart attack). In this case, some children need medicines such as aspirin or other blood-thinning treatments to help protect the heart.
The risk of a heart attack is very low overall. The risk is highest in the first 2–3 months after KD begins and is mainly seen in children who develop large aneurysms or who have ongoing inflammation.
How a child progresses in the long-term depends on several factors, including: how early treatment was started, the size of any aneurysms, and the child’s age at the time of illness. Younger children are more likely to develop aneurysms but also have a higher likelihood of resolution. With prompt treatment using IVIG therapy and other anti-inflammatory medicines, aneurysms are now more likely to improve or disappear than in the past. Smaller aneurysms are especially likely to return to normal.
Children who continue to have moderate or large aneurysms need lifelong care with a heart specialist. As they grow older, their care is usually transferred from a paediatric cardiologist to an adult cardiology team. These children may have a higher chance of heart problems later in life, such as coronary artery disease, heart attacks, or heart failure. Regular check-ups, heart monitoring, and steps to support good heart health (such as healthy lifestyle habits and, when needed, medication) help to reduce these risks and protect long-term wellbeing.What are the current recommendations around future treatment and monitoring?
After a child’s initial illness, follow-up visits may be arranged with different paediatric specialists, often together with the child’s regular GP. These early visits help make sure the acute illness has settled.
Long-term monitoring is usually managed by a paediatric cardiologist. This care includes heart tests such as an echocardiogram, which is an ultrasound scan that shows how the heart muscle and heart vessels are working. Most treatment centres in Australia follow recommendations from the American Heart Association, which outline how often these scans should be done.
For most children without coronary aneurysms (abnormal widening of the heart’s blood vessels), an echocardiogram is performed at the time of diagnosis and again within four to six weeks. If this test is normal, then further follow up may not be required.
Children who do have coronary aneurysms, or who are considered at higher risk of developing them, will need more frequent echocardiograms. These regular scans help the cardiologist keep track of any changes in the size of the coronary arteries and check how well the heart is functioning over time. Further echocardiograms may be done at longer intervals – often months or years apart – depending on how the heart looks and how a child is recovering. In some situations, additional heart tests such as exercise (stress) tests or more detailed imaging (for example, CT or MRI scans) may be recommended.
If a child has a coronary aneurysm and needs anti-clotting (anticoagulation) medication, they will also have follow-up appointments with a haematologist while they remain on this treatment.
What are the short-, medium- and long-term impacts on behaviour, brain development and growth? Is there a link to ASD and ADHD?
Children with acute KD are irritable when they have the acute illness with fever and inflammatory symptoms and often this will affect their behaviour as would any other significant illness. After treatment with IVIg and these acute symptoms settle down many families report that the children continue to have some issues with poor sleep, possibly as a result of the disturbance resulting from the hospital environment, anxiety, IVIg treatment or possibly just their bodies recovering from the significant illness. This usually lasts only a few weeks and then children are back to their usual selves.
There has been a lot of discussion about whether KD might be linked to autism spectrum disorder (ASD), but this is very difficult to prove or disprove. At present, there is no proven link between KD and ASD. Researchers have compared large groups of children who have had KD with children of the same age and sex who have not had the illness (known as “control” groups) to see if ASD is more common after KD. The results of these studies have been mixed and not consistent.
A recent systematic review and meta-analysis, which brought together data from many previous studies involving nearly 1.5 million children, did not find a clear association between KD and ASD or intellectual disability. The study did find that children who have had KD were more likely to be diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) compared with children who had not had KD.
The reason for this finding is not yet understood, and more research is needed to explore whether it relates to the illness itself, its treatment, or other factors.Could we build into the IVIg request/consent that parents are asked to donate blood?
IVIg is made from donated plasma, and an IVIg infusion is a blood transfusion – even if it might not look like one! Therefore, an informed discussion and consent to receive treatment prior to receiving IVIg is essential, so that the risks and benefits can be understood and a decision made. To receive government-funded IVIg, it is also a requirement that basic information about the patient and their condition is provided to the Australian Red Cross Lifeblood and the National Blood Authority by the requesting doctor so that it can be understood how IVIg is being used in Australia (for example, how many patients with various conditions need the product, and what doses they receive).
Only 3% of the Australian population donates blood – and probably many more people could do so, but they’ve either never thought of it, or are not sure whether they could. Many people are also not aware that IVIg comes from blood, so they’ve never made the connection with the need for plasma donations.
However, not every person is able to give blood. This might be for temporary or for ongoing reasons to do with the donor’s safety. For example, pregnancy, recent surgery or infection might mean that someone can’t donate right now; and other major health conditions might mean that someone might not be able to donate in the future. Other reasons, including some illnesses or recent travel to certain destinations might have to do with safety of a potential recipient of that donation. Therefore, it is unlikely that requiring or even requesting a parent or family member to consider blood donation as a necessary pre-condition for a child with KD (or any other illness) to receive IVIg therapy – that wouldn’t be fair.
But, since most people in the community are able donate blood safely, the more people who do so the better off everyone will be – every donation contributes to Australia having an adequate supply of all the different blood products we need, including immunoglobulins.
So, please consider if you can be a blood donor, and encourage people you know to donate blood too! Australian donor eligibility criteria and information about blood donation is available here: https://www.lifeblood.com.au/donors/blood-plasma-platelets/making-a-donation