A teacher has been criticised by a mother who claims they told a five-year-old cancer survivor that she couldn’t be pretty and bald.

Five-year-old MaKayla Welsh has been battling leukaemia for almost two years and her hair has started to fall out from her chemotherapy treatment.

MaKayla’s mother, Nicole Welsh, claims a relief teacher at her daughter’s US primary school shamed her in front of her classmates.

"The teacher thought she was pulling her hair out. The teacher told her that if she was bald she wouldn't be pretty," Ms Welsh told Channel 11 News.

After reporting the incident to the school’s principal Ms Welsh was told that the issue had "been handled".

"[They] promised she'd never go through anything like that again,” she said.

The five-year-old girl, who is currently in remission, struggles with her hair loss.

"It did bother her that she was losing her hair again," Ms Welsh told Channel 11 News.

"It bothered her to the point that she told me she wasn't going to school again once it was gone."

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Following the incident, the Pennsylvania school showed a video to help educate students about MaKayla's condition.

“When the video was done, the whole class rallied around and hugged her. She was excited and couldn't wait to go to school [the next day],” said her mother.

Mrs Welsh says the little girl is beautiful "all the time".

"I don't care whether she has hair or not," she said.

The school gave no indication if the teacher has been disciplined. They declined to comment to local media.

For more on MaKayla Welsh visit her GoFundMe page here.