What Is Kawasaki Disease? Symptoms, Causes, Diagnosis, and Treatment

Kawasaki disease is a condition that causes inflammation of the blood vessels, and mostly affects children under 5 years old. (1,2)

Along with inflammation of the blood vessels and several days offever, other symptoms include rash; swollen neck glands, hands, and feet; and red eyes, lips, and tongue, according to the American Academy of Pediatrics (AAP). (2)

It is a leading cause of acquired心脏病在美国,根据中心Disease Control and Prevention (CDC). (1) But with early detection and treatment, long-term heart issues are unlikely to occur. (2)

“最严重的可能后果是供应血液的血管发炎。我们治疗川崎病的主要原因是试图防止这些可能的心脏结果。”Vijaya Soma, MD, a clinical assistant professor in the department of pediatrics at New York University's Grossman School of Medicine, who specializes in pediatric infectious disease.

Kawasaki disease has three distinct phases.

在川崎病的第一阶段会发生什么？

According to the Kawasaki Disease Foundation, phase 1 symptoms include: (3)

• 高的fever(commonly above 102.2 degrees F) that lasts for at least five days
• Pink eye(conjunctivitis) that does not cause a thick discharge
• 皮疹，特别是在身体或生殖器区域的树干上
• 红色，干燥，破裂的嘴唇
• Very reddened,swollen tongue（这称为草莓舌）
• 红色的手掌的手掌和脚底
• Swollen lymph nodes in the neck

What Happens in Phase 2 of Kawasaki Disease?

In phase 2, the following symptoms may develop:

• Peeling of the skin on the hands and feet, particularly on the tips of the fingers and the toes
• 关节疼痛
• 腹泻
• 呕吐
• Stomach pain

What Happens in Phase 3 of Kawasaki Disease?

In the third phase, symptoms slowly begin to disappear if there are no complications.

“Most patients do well after treatment,” saysMichael Portman, MD, the director of research in the division of cardiology at Seattle Children’s Hospital who studies Kawasaki disease. “The fever usually goes away, but children can take up to a month to totally feel normal again.”

医生不知道是什么原因引起川崎病，但是有证据表明病毒或感染会触发异常immune systemresponse in children who are genetically predisposed to the condition, according to Merck Manual. (4)

“The general theory is that there is an infection that precedes Kawasaki disease, and this serves as a trigger for an immune response in a genetically susceptible child,” says Dr. Portman.

Genetics appear to play a role in Kawasaki disease, but scientists are still trying to understand these factors, according to the Genetic and Rare Diseases Information Center. (5)

Kawasaki disease is more common in Asian and Asian American populations and among family members of children who have the condition, which suggests that the disease may have a genetic component. Moreover, certain gene variants are associated with an increased risk of developing Kawasaki disease.

Children of parents who have had Kawasaki disease are twice as likely to develop the condition compared with the general population, and children whose siblings have had Kawasaki disease are 10 times more likely to develop the disorder. That said, it’s still rare for more than one child in a family to have the disease.

Risk Factors

川崎病的危险因素包括:

• Being male
• Being between 6 months and 5 years old
• Having a family history of the disorder

Kawasaki disease is not contagious.

There is no specific test to diagnose Kawasaki disease. (2)

“Kawasaki disease has many characteristics similar to other childhood diseases, which makes it difficult to diagnose for those unaware of it,” says Portman. “Any parent should be suspicious if their child has continuing fever for four days or longer, along with swollen hands, red eyes, red, cracked lips, and a rash, particularly if they are given antibiotics and the fever does not go away.”

Doctors make a diagnosis of Kawasaki disease if a child has had a fever for five days or more and if they have at least four of the following five symptoms: (4)

• Red eyes without discharge
• Reddened, dry, cracked lips and a strawberry tongue
• 肿胀，红色和剥皮的手和脚
• Red, patchy rash on the trunk of the body
• Swollen, tender lymph nodes in the neck

Blood tests, urine tests, and throat cultures may also be conducted to rule out other conditions that cause similar symptoms. (2,4)

Once Kawasaki disease is diagnosed, your child’s doctor may order electrocardiography (ECG) and ultrasonography of the heart (超声心动图) to look for heart problems such as coronary artery aneurysms. (4)

Your doctor may also refer you to apediatrician具有传染病，风湿病或心脏病学专业。（2）

Prognosis of Kawasaki Disease

通过早期治疗，几乎所有儿童都从川崎疾病中康复。（4）在症状的前10天内进行的治疗大大降低了冠状动脉损害的风险，并有助于解决其他症状。

Without treatment, up to 25 percent of children develop heart problems such as coronary artery动脉瘤, which typically begin one to four weeks after the onset of Kawasaki disease. Treatment lowers the risk of heart complications to about 1 in 20. In children who are not treated, the death rate is about 1 percent (death almost always occurs in the first six months of life but can happen up to a decade later). If a child develops aneurysms, they have an increased risk of having heart problems as adults, even if the aneurysms resolve.

But if your child doesn’t develop a coronary动脉瘤, they are likely to have an excellent long-term outcome, according to the AAP, which says that after treatment, children will benefit from aheart-healthy diet和生活方式，并监视胆固醇水平。（2）

Kawasaki disease may last from 2 to 12 weeks or longer. (4)

药物选择

The standard treatment for Kawasaki disease consists of high doses of bothaspirin和immunoglobulin, which is a purified form of proteins and antibodies from donated blood. (1,4) These treatments can substantially reduce the risk of serious heart complications, and should be started as soon as possible. (4)

For one to four days, immunoglobulin is administered intravenously, andaspirinis given orally. When the child has no fever for four to five days, the dose of aspirin is lowered. But children with Kawasaki disease must continue to take aspirin for at least eight weeks from the onset of the illness.

If there are no coronary artery aneurysms and no further signs of inflammation, aspirin may be discontinued. But children with coronary artery abnormalities need long-term treatment with aspirin. It’s important to note that aspirin can cause a serious liver condition called Reye's syndrome, so it should be given to young children only under a doctor's supervision. (2)

Additional treatments may be required if a patient does not respond well to the initial dose of immunoglobulin, their fever comes back, or there are abnormal findings on the first超声心动图。In these cases, doctors may recommend another dose of immunoglobulin or other medications that fight inflammation, such as steroids,infliximab, oretanercept。

患有大型冠状动脉瘤的儿童可以给予抗凝剂，这些药物是防止血液凝结的药物。（4）

The most serious potential complication of Kawasaki disease is the development of a coronary artery aneurysm, which is a bulge in the wall of the arteries that supply blood to the heart. Coronary artery aneurysms can rupture or cause a blood clot, leading to a heart attack and sudden death.

“在接受免疫球蛋白治疗治疗的儿童中患冠状动脉疾病的风险很低。”Daphne T. Hsu, MD, the division chief of pediatric cardiology and the codirector of the pediatric heart center at Children's Hospital at Montefiore in New York City. “Even though the risk is low, it is important that the child be followed closely in the first six weeks after the diagnosis [of Kawasaki disease] is made to see if the coronary arteries show signs of being affected.”

Portman adds that some children may have problems with their heart for the rest of their lives. Some may need special procedures or surgery to keep the coronary arteries open. In these cases, they will be monitored by a pediatric心脏病专家as they grow up.

Other possible complications include painful inflammation of the tissues lining the brain (meningitis), ears, eyes, liver, joints, urethra, andgallbladder。（4）

Also, the AAP recommends that live viral vaccines be postponed for 11 months after a child is treated for Kawasaki disease, because the treatment may reduce the effectiveness of vaccines for illnesses includingMMR (measles, mumps, rubella)和varicella(chicken pox). Children older than 6 months of age should also get the inactivatedinfluenza (flu) vaccine。

According to the CDC, Kawasaki disease affects about 9 to 20 per 100,000 children younger than 5 in the United States. (1) It is estimated that more than 4,200 children are diagnosed with Kawasaki disease in the United States each year. (3)

According to the AAP, 80 to 90 percent of cases of Kawasaki disease happen in children older than 6 months and younger than 5 years. (2) It is less common for older children and adolescents to get the disease, but it does happen.

The average age of children who develop Kawasaki disease is 2 years old, and boys are 1.5 times more likely than girls to develop the condition, according to the American Heart Association. (6)

Kawasaki disease predominantly affects children of Japanese and Korean descent, according to KidsHealth. (7) While it is more prevalent among children of Asian and Pacific Islander descent, the condition affects children of all racial and ethnic groups. (3)

Multisystem inflammatory syndrome in children (MIS-C) — a rare but serious complication associated with COVID-19 that causes inflammation in various body parts — reportedly features some Kawasaki disease-like features, like fever, rash, and bloodshot eyes. (1)

More than half of children with MIS-C are Black, according to a small study published in May 2020 in theBMJ。(8)

It’s important to note that Kawasaki-like multisystem inflammatory syndrome associated with COVID-19 has characteristics that differ from those of classic Kawasaki disease, according to the study. In addition to it being more common among children of African ancestry, it also features predominant acutegastrointestinalsymptoms, hemodynamic instability (abnormal or unstable blood pressure), andmyocarditis(inflammation of the heart muscle).

Kawasaki disease may be mistaken for the following other conditions that can cause similar symptoms: (4)

• Measles
• Scarlet fever
• Juvenile idiopathic arthritis

American Academy of Pediatrics

The AAP’s HealthyChildren.org website is supported by 67,000 pediatricians committed to the physical, mental, and social health and well-being of all children. HealthyChildren.org features information about signs and symptoms, complications, and treatment of Kawasaki disease.

Kawasaki Disease Foundation

KDF是唯一专门针对与川崎疾病有关的问题的非营利组织。它的网站上有关于川崎疾病，教育和支持资源和患者故事的经常询问的问题。

Genetic and Rare Diseases Information Center

GARD is a program of the National Center for Advancing Translational Sciences (NCATS) and is funded by parts of the National Institutes of Health. Its website features information about the symptoms, causes, and treatment of Kawasaki disease.