The first suspected cases of a rare inflammatory disease striking children and young adults have been reported in South Korea, health authorities said Tuesday, issuing special warnings as preschools and primary schools are set to resume in-person classes Wednesday.

The Korea Centers for Disease Control and Prevention’s Deputy Director Kwon Jun-wook said in a Tuesday press briefing that two pediatric patients at health care institutions in Seoul might have the little-known condition, now called multisystem inflammatory syndrome in children or MIS-C.

While doctors are still looking into what may be Korea’s first cases of MIS-C, one of the two children fits the preliminary case definition developed by the World Health Organization, he said.

Pediatric infectious disease specialist Dr. Eun Byeong-wook of Nowon Eulji University Hospital in northern Seoul said in a phone interview that the inflammatory condition appears to have characteristics of Kawasaki disease.

The condition is accompanied by Kawasaki-like symptoms such as skin rashes and fever, as well as other symptoms not typically observed in Kawasaki patients such as abdominal pain, a drop in blood pressure, slowed cardiac contractions and toxic shock, he said.

Treating the condition would involve forms of anti-inflammatory therapy such as immunoglobulin injections and steroids.

Eun said the syndrome’s links to the novel coronavirus, which causes the respiratory disease COVID-19, were still being investigated, adding that none of the 788 coronavirus cases in patients under 19 here have been severe so far.

The WHO’s scientific brief, dated May 15, says that while the full spectrum of the syndrome is not yet clear, “Initial hypotheses are that this syndrome may be related to COVID-19.”

In a web statement updated May 21, the US Centers for Disease Control and Prevention said although the cause of MIS-C is unknown, many children with the syndrome there had COVID-19, or had been around someone with the coronavirus.

Korea is experiencing renewed flare-ups of COVID-19, with the daily tally of new infections recording 19 on Monday.

Since the first case was reported Jan. 20, Korea had tested 839,475 people as of Tuesday, 11,225 of whom were confirmed to have the coronavirus. A total of 10,275 former patients had been discharged from care upon recovery, and at least 269 had died from the infection.

Minister of Health and Welfare Park Neung-hoo said in a Tuesday meeting of the Central Disaster Management Headquarters that additional measures would be taken to boost coronavirus protection for some 390,000 undocumented immigrants who may not be getting medical help.

“To stem transmission within communities, disease control systems should not leave anyone behind -- especially the most vulnerable in society,” he said.

The minister once again warned against visiting high-risk settings such as bars and karaoke lounges, which have recently emerged as sites of fresh outbreaks.

On May 6, when the government relaxed its physical distancing guidance, a 29-year-old man with COVID-19 was found to have visited nightclubs in Itaewon, central Seoul, while infectious.

Health officials have tested 41,340 people with ties to the nightclubs and confirmed that 118 had contracted the disease. A further 272 are undergoing testing.

In Incheon, a city northwest of Seoul, 66 high schools have had to postpone reopening last week as two students came down with the coronavirus after visiting karaoke facilities.

Amid the scramble to trace the source of the infections, health officials report difficulties in identifying those who have been exposed to the virus and in tracing their contacts due to false accounts and incomplete registries.

In response, the government said businesses and other establishments deemed to carry high risks of contagion are required to keep digitized logs of all visitors starting early next month.

“Our best line of defense remains keeping good hygiene, wearing face masks in public spaces and exercising caution when socializing,” said Kwon of the KCDC.

By Kim Arin (arin@heraldcorp.com)