Pediatric Cardiology

Kawasaki Disease in Children: Symptoms, Causes and Treatment Options

Posted on by Prof. Dr. İbrahim Cansaran TANIDIR

Kawasaki disease is a systemic illness of childhood that develops suddenly and causes widespread inflammation of the walls of blood vessels (vasculitis) throughout the body. Because it has the potential to affect the coronary arteries that supply the heart, it is a critical pediatric condition that must be recognized early and managed with appropriate clinical interventions. Timely medical treatment is essential for preserving the healthy structure of the blood vessels and preventing permanent cardiac damage. Thanks to current medical protocols, this excessive immune system response can be successfully controlled, allowing children to continue their healthy development safely.

Who Is Affected by Kawasaki Disease and Which Age Groups Are Most Commonly Involved?

Although the disease has the potential to occur in individuals of any age, more than eighty percent of cases are observed in children under five years of age. It is particularly common in children around two to three years old. Clinical findings may occasionally be seen in infants younger than six months or, less frequently, in older children. When evaluated according to sex, boys are considered to be slightly more susceptible than girls. In terms of geographical distribution, the disease is known to occur much more frequently in Asian populations than in the rest of the world. Although its frequency in our country is closer to the statistics reported in Western countries, careful monitoring is still required because diagnostic challenges may increase the likelihood of cardiac involvement. Seasonal variation is also observed, with incidence generally increasing during winter, the end of autumn, and seasonal transitions in spring.

The risk of death during the initial acute febrile phase of the disease is extremely low. The primary concern is identifying and preventing hidden coronary artery enlargement before it progresses. Blood vessel inflammation that occurs during childhood and goes unrecognized may contribute to certain heart problems later in adulthood. Some unexplained coronary artery disorders seen in adults may have their origins in this disease. Family genetics may also influence the process; if one sibling has experienced the disease, genetic susceptibility should be considered, and closer observation of the other children in the family is recommended. Recurrence of the disease in the same child later in life is quite rare.

How Does Kawasaki Disease Affect the Body and What Causes It?

Although the underlying triggering mechanisms continue to be investigated, current evidence suggests that the disease results from a combination of genetic predisposition and infectious agents from the environment. In a genetically susceptible child, a simple viral or bacterial infection may suddenly activate the immune system. At this point, instead of fighting microorganisms, the immune system mistakenly targets the body’s own healthy blood vessel walls, triggering an inflammatory attack. The affected vessels are usually medium-sized arteries, with the coronary arteries that directly supply the heart being among the primary targets of this misdirected immune response.

This inflammatory process causes changes within the body in three distinct stages. During the initial acute phase, immune cells weaken the structure of the vessel wall. As the vessel wall loses its strength, the pressure of flowing blood may cause it to balloon outward, forming aneurysms. During the second stage, which may last for months, the intense inflammation gives way to a quieter but ongoing structural deterioration. In the final healing phase, the body attempts to repair the damaged vessel wall by producing new cells. However, this healing tissue may narrow the vessel lumen, making blood flow more difficult. This is why families are frequently informed that Kawasaki disease cannot be managed with fever-reducing medications alone.

What Symptoms May Suggest Kawasaki Disease in Your Child?

There is no single laboratory value that definitively confirms the diagnosis of Kawasaki disease. Therefore, diagnosis depends largely on the physician carefully evaluating all clinical findings together. The symptom that most often draws parents’ attention is persistent fever that does not respond as expected to routine fever-reducing medications or antibiotics. This fever usually lasts for five days or longer. Along with fever, several characteristic physical changes are expected to be present.

Clinical signs that may accompany the fever include:

  • Persistent high fever that cannot be reduced
  • Redness in the whites of the eyes
  • Severely dry lips
  • Cracked lips with occasional bleeding
  • Strawberry-like tongue
  • Red rash on the trunk
  • Firm redness of the palms
  • Firm redness of the soles of the feet
  • Mild swelling of the fingers
  • Swelling of the toes
  • Peeling around the junction of the nails and skin
  • Enlarged lymph nodes in the neck

The redness of the eyes differs from that seen in ordinary infections because there is no pus or sticky discharge; instead, there is marked conjunctival redness. The lips become bright red and may crack and bleed easily. The tongue develops prominent papillae, giving it a characteristic strawberry-like appearance. Red skin rashes are commonly concentrated on the abdomen and upper legs and do not form blisters like chickenpox. During the first days of the illness, firm swelling of the palms and soles may be noticeable, followed in subsequent weeks by characteristic peeling around the fingernails and toenails. Swollen lymph nodes are usually found on one side of the neck and may be visibly enlarged.

What Is Atypical Kawasaki Disease and How Does It Affect Other Organs?

Diseases do not always follow textbook patterns. Some children do not exhibit all of the classic symptoms, yet they continue to have persistent unexplained fever. These cases are referred to as incomplete or atypical Kawasaki disease. This presentation is especially common in infants younger than six months, whose bodies may not show sufficient clinical signs. In these infants, the only notable finding may be high fever accompanied by extreme irritability. In such atypical cases, involvement of other organ systems often provides valuable diagnostic clues.

Findings affecting different organ systems that may support the diagnosis include:

  • Pain in the knees or elbows
  • Swelling of large joints
  • Severe diarrhea
  • Persistent abdominal pain
  • Gallbladder distension
  • Elevated liver enzyme levels
  • Excessive sleepiness
  • Inflammation of the inner layers of the eye
  • Inflammatory cells in the urine
  • Mild infiltrates in the lungs

Digestive system symptoms may be particularly prominent. Elevated liver enzymes or a distended gallbladder seen on ultrasound may point toward the diagnosis. Severe abdominal pain may even cause children to refuse feeding. Involvement of the musculoskeletal system may result in knee joint swelling and difficulty walking. When the nervous system is affected, excessive sleepiness can become particularly distressing for families. Urinary findings may resemble urinary tract infections, while lung involvement may sometimes lead physicians toward an incorrect diagnosis of another infectious disease.

What Are the Main Differences Between Kawasaki Disease and MIS-C?

Multisystem Inflammatory Syndrome in Children (MIS-C), which has gained attention in recent years, is one of the conditions that most closely resembles Kawasaki disease. Both disorders cause widespread inflammation, skin redness, conjunctival injection, and potential heart involvement. Nevertheless, they differ in their biological basis, the age groups they primarily affect, and the pattern of organ involvement.

The main distinguishing features include:

  • Primary age groups affected
  • Triggering factors
  • Severity of gastrointestinal symptoms
  • Degree of weakening of heart muscle function
  • Tendency toward coronary artery aneurysm formation
  • Platelet count changes

A clear distinction is observed in terms of age. Kawasaki disease mainly affects infants and preschool-aged children, whereas MIS-C is more commonly seen in school-aged children and older individuals. Regarding cardiac involvement, Kawasaki disease primarily raises concern about coronary artery aneurysms, whereas MIS-C is more strongly associated with reduced heart pumping function and severe circulatory impairment. Gastrointestinal symptoms are generally much more severe in MIS-C. Differences in laboratory findings also help distinguish these two conditions reliably.

Which Tests and Diagnostic Methods Are Used for Kawasaki Disease?

As clinical suspicion increases, laboratory tests become one of the most valuable diagnostic tools. Various blood tests are ordered to determine the degree of inflammation within the body. White blood cell counts may become significantly elevated. Markers such as C-reactive protein (CRP), which is produced by the liver and indicates inflammation, are often well above normal limits. Albumin levels, which provide valuable information regarding treatment response, are also carefully evaluated. Low albumin levels indicate the extent to which inflammation has affected the blood vessel walls.

Laboratory factors considered when identifying high-risk patients include:

  • Markedly elevated white blood cell count
  • Lower-than-expected albumin levels
  • Very high CRP levels
  • Lower-than-expected hematocrit levels for age
  • Increasing platelet counts
  • Age younger than one year

If several of these laboratory abnormalities are present, the likelihood of coronary artery enlargement is considered higher. Young infants and children with these laboratory findings require especially close monitoring. However, no scoring system can replace careful clinical judgment, and treatment intensity is adjusted according to both clinical findings and imaging results.

How Are the Coronary Arteries Evaluated in Kawasaki Disease?

Children with persistent fever and suspected Kawasaki disease should undergo evaluation by a pediatric cardiologist. Echocardiography is one of the most valuable diagnostic tools available. The examination is completely painless and does not involve radiation exposure. Since children differ in height and weight, there is no single standard measurement for coronary artery size. Therefore, measured vessel diameters are indexed to body surface area and converted into statistical Z-scores that guide treatment decisions.

The coronary artery findings that may be detected on imaging include:

  • Completely normal dimensions
  • Irregular vessel wall appearance and increased brightness around the artery
  • Mild and temporary dilatation
  • Small aneurysms
  • Medium-sized aneurysms carrying moderate risk
  • Giant aneurysms

The treatment plan is determined according to these findings. A child with mild coronary artery enlargement requires a different medication regimen from one with marked aneurysmal dilatation. Electrocardiograms (ECGs) are also obtained periodically throughout follow-up to evaluate potential disturbances in the heart’s electrical conduction or rhythm.

How Is Kawasaki Disease Treated During the Acute Phase?

During the initial phase of intense fever, the primary goal is to suppress the excessive immune response as early as possible and protect the coronary arteries. The optimal treatment window is within the first ten days after symptom onset. The cornerstone of therapy consists of administering immune-supportive antibodies through a slow intravenous infusion over many hours. This intravenous immunoglobulin treatment significantly helps calm the immune system’s attack against the body’s own tissues and allows fever to resolve rapidly in most children.

Acetylsalicylic acid is administered in addition to intravenous immunoglobulin. Although it is generally avoided in young children with most febrile illnesses, it plays an important role in controlling widespread inflammation in Kawasaki disease. It is initially prescribed at higher doses to reduce fever and inflammation and later decreased once the child enters a stable phase. At lower doses, its primary purpose is to maintain smooth blood flow by preventing clot formation, and treatment may continue for an extended period according to the physician’s recommendations.

What Happens If Kawasaki Disease Does Not Respond to Treatment?

Most children show significant improvement after the initial course of intravenous immunoglobulin. However, fever may occasionally persist despite adequate time having passed or may recur shortly afterward. These cases are referred to as treatment-resistant Kawasaki disease. Persistent fever indicates ongoing inflammation and may increase the risk of coronary artery involvement. In such situations, a second course of intravenous immunoglobulin may be administered. If there is still no response, stronger immunosuppressive medications such as corticosteroids are considered. In especially resistant cases, biologic therapies targeting inflammatory pathways at the cellular level may also be evaluated.

How Should Children Be Followed After Hospital Discharge Following Kawasaki Disease?

Once the child’s condition has stabilized, fever has resolved, and no progression of coronary artery involvement is observed, discharge from the hospital is planned. However, discharge does not mean that follow-up has ended. Children whose coronary arteries remain completely normal generally require only short-term follow-up before returning to their normal lives. In contrast, children with persistent coronary artery abnormalities require long-term cardiology follow-up. Regular echocardiographic examinations are scheduled, and careful attention is given to maintaining low-dose medications that help support coronary artery health.

How Should Daily Life, Vaccinations, and Sports Be Planned After Kawasaki Disease?

The recovery period requires families to pay close attention to several important issues at home. The medications used during treatment necessitate adjustments in certain social activities and vaccination schedules.

The most important considerations during this period include:

  • Postponing live-virus vaccines
  • Receiving annual influenza vaccination
  • Avoiding contact with individuals who have chickenpox
  • Seeking immediate medical attention after possible chickenpox exposure
  • Taking blood-thinning medications without missing doses
  • Avoiding sports with a high risk of collisions or trauma
  • Choosing calmer activities that do not excessively strain the heart
  • Taking all additional medications prescribed by your physician regularly

Because high-dose intravenous immunoglobulin therapy may temporarily reduce the effectiveness of live-virus vaccines, vaccination schedules are postponed accordingly. Children receiving long-term preventive medications should also be protected carefully against influenza and chickenpox. Children with coronary artery enlargement are advised to avoid sports that markedly increase heart rate or involve significant physical contact. Children who recover completely with normal coronary arteries may gradually return to their usual games and school activities without restriction.

Güncellenme Tarihi: 13.10.2026

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