Mouth ulcers or sores can unsettle your tot and make him cranky. Find out how to ease his discomfort.


Working mum Valerie Ng was horrified when her school sent her son, Gabriel, 4, home from his childcare centre last year because he had two mouth ulcers. The teacher had called her while she was at work, to take him home because she suspected that he had Hand, Foot, Mouth Disease (HFMD).

“From what I know, Gabe had been in perfect health, and it was completely unexpected, so I panicked and rush down,” she recalls.

Gabriel did, indeed, have two mouth ulcers inside his lower lip, but he was not having a fever, nor did he have any spots on his hands. “The teacher said that he didn’t want to have his breakfast in school and didn’t want to drink water. It’s understandable because the ulcers might have been making him uncomfortable,” Ng says.

Ng took her son to the paediatrician immediately. But after an examination, it was determined that Gabriel did not have HFMD ― he had probably bitten his lip accidentally.

Ulcers can also occur when children are feeling tired or stressed, or where there is a family history of recurrent mouth ulcers.

“I was relieved because finding alternative childcare arrangements would have been a nightmare,” says Ng. She adds that she understood the school’s rationale for taking precautions because “the incidence of HFMD was also at a peak during that time”.

So, what exactly are these mouth ulcers, also known as mouth and canker sores? Dr Tan Zhen Han, a paediatrician at SBCC Baby & Child Clinic (Bukit Panjang), fills us in.

What causes mouth ulcers in toddlers and young children?
There are numerous causes of mouth ulcers in toddlers and young children, but they usually occur following some trauma to the mouth. These include mechanical trauma from accidentally biting the tongue or inside of the cheek, overchewing hard foods, or even from vigorous toothbrushing, as well as thermal injury from hot foods.

Infections are another major cause of oral ulcers in children. Common viral infections HFMD, chickenpox, and herpes gingivostomatitis (cold sore). In such cases, there may be accompanying symptoms such as fever, feelings of discomfort or rashes.

Ulcers can also occur when children are feeling tired or stressed, or where there is a family history of recurrent mouth ulcers.                                          

Rarely, mouth ulcers can sometimes with associated with an underlying medical condition, such as vitamin deficiencies (for example, iron, vitamin B12, folate, vitamin C, zinc, and magnesium), an impaired immune system, and gastrointestinal tract disease.