Singapore could be heading for one of its worst hand, foot and mouth disease (HFMD) outbreaks, with infections hitting near- record numbers over the past few months.

The 18,241 infections so far are the second highest for the first 21 weeks of a year, exceeded only by the 21,102 in 2012. In contrast, the median number for the same period over the past five years is 8,193.

Associate Professor Chong Chia Yin, a senior infectious disease consultant at KK Women's and Children's Hospital, said more than 200 children have been hospitalised there for HFMD this year.

"Most of these children were admitted for fever and poor feeding, mild dehydration or febrile fits due to their high fever. None suffered serious complications," she said.

Serious complications are rare, but the infection could damage the brain, lungs or heart. Symptoms of HFMD include fever, ulcers in the mouth and on the tongue, blisters on the hands, feet and buttocks, poor appetite and lethargy. A child can become dehydrated from not drinking enough because it hurts to do so.

During an outbreak of HFMD in 2000-2001 associated with the more dangerous EV71 strain, there were seven deaths.

The current epidemic has been fuelled in part by parents who send their sick children to childcare centres, and refuse to take them home when asked to do so.

Madam Marjorie Zaccheus, principal of Presbyterian Community Services Tampines Childcare Centre, which has been hit by a spate of cases, said that when she suspects a child has HFMD, she keeps him away from other children and asks his parents to take him home.

"The parents say they are coming but they don't turn up until closing time. Others don't answer the phone," said Madam Zaccheus.

She said that holding a full-time job is no excuse. "If both parents are working, they should look for alternative care. They should have someone to look after their children in case of sickness or emergencies. What will they do if the centre has to close?" she added.

The children are checked for fever and ulcers or rash when they arrive. But Madam Zaccheus said that, sometimes, the person accompanying the child is not a parent or guardian. "In these cases, I have to accept them. I have no alternative."

But the centre, which has 79 children, does not have the resources to effectively quarantine a sick child. It had 20 HFMD cases in the last month and a half.

Mr Joe Tan, 38, whose three-year-old daughter was one of the 20 infected, said: "It's irresponsible for parents to leave a sick child here."

He added: "Not only is the child already uncomfortable because of the sickness, but he would also feel lonely and isolated if he has to be separated from the other children."

Despite the high rates of infection at the centre, many parents have chosen not to keep their children away.

"I'm definitely concerned but, as a working parent, I don't have much of a choice. All I can do is pray for the best for my kid," said accountant Rosalind Goh, whose son has not contracted HFMD.

Adults, too, can get HFMD and it is usually more severe.

Mr Tan recalled that when his wife Oon Bee caught the infection from their infant son some years back, she was sick in bed for a week with high fever and had a hard time eating because her mouth was full of ulcers.