The number of Japanese suffering from Kawasaki syndrome, an autoimmune disease that mainly afflicts children and whose cause and cure remain unknown, has been steadily increasing, a recent nationwide survey showed.
The total number of patients under age 4 stood at 12,755 in 2010, exceeding 10,000 for the sixth straight year, according to the biannual survey.
Of even greater concern, the disease’s incidence per 100,000 children under 4 came to 239.6, the highest rate recorded since the study began in 1970, eclipsing the rate of 219.9 seen in 2008.
The 2010 total also was the third-highest level on record, after the 15,519 incidences in 1982 and the 12,847 cases four years later.
Kawasaki syndrome is the most common cause of acquired heart disease among children in developed countries. It is an acute febrile illness of unknown etiology that primarily affects children younger than 5, and can damage coronary arteries supplying the heart, triggering a heart attack.
“The incidence of the disease has been rising steadily since the mid-1990s, although we don’t know exactly what has been behind the latest increase,” said Yoshikazu Nakamura, a public health professor at Jichi Medical University in Tochigi Prefecture.
The survey was led by a professor at the university. It collected data in 2009 and 2010, covering 2,033 medical institutions with pediatric departments. Of these, 1,445 submitted valid responses.
Kawasaki syndrome was first discovered in Japan, when pediatrician Tomisaku Kawasaki diagnosed the disease in 1967. Since then it has been found worldwide in children of all ethnic origins.
The cause of Kawasaki syndrome has yet to be identified, but it is widely believed that viral or bacterial infections can spark an autoimmune reaction in the patient, possibly causing coronary artery aneurysms.
It inflames small and medium-size blood vessels throughout the body, especially in coronary arteries.
Major symptoms include high fever, strawberrylike red bumps on the tongue, swollen lymph nodes in the neck, skin rashes and bloodshot eyes.
The standard treatment is intravenous immunoglobulin (IVIG), produced using antibodies from the blood of 3,000 to 10,000 healthy donors.
When administered in high doses, the treatment considerably reduces the symptoms of most Kawasaki syndrome patients, including inflammation.
Still, IVIG is not effective on 20 percent of patients, prompting researchers to look for other treatments, including steroids.
A research team at the health ministry conducted a clinical trial of steroids from September 2008 to December 2010 at 74 medical institutions across the country involving patients with potentially serious afflictions.
The patients were divided into two groups. One was treated only with IVIG and the other with both IVIG and steroids.
The trial found that 23 percent of those in the first group contracted coronary artery aneurysms, but the symptom was detected in only 3 percent of patients administered both IVIG and steroids.