Her face is disfigured by a wide gaping hole, her nose and right cheek eaten away by necrosis, a rare form of rapid cell degeneration.

But the 18-year-old, whose story focuses attention on the poor state of medical care in Cambodia, is not giving up as residents of Phnom Penh raise funds through the website Just Giving after the Phnom Penh Post revealed her plight.

In December, Soth Rey was working in a massage parlour to help support her parents and three younger siblings in the north-western town of Siem Reap when she fell ill with a sinus infection. A doctor diagnosed the flu and sent her home.

Weeks later she developed ulcers in her nose and the doctor decided to pull out some of her teeth.

When that didn't solve the problem, she went to a traditional Khmer healer who spat and blew on the ulcers for a month. The illness persisted.

Then Soth Rey's face began to disintegrate.

Critically ill in late February, her family brought her to Phnom Penh but did not have the money for her treatment.

An online plea for donations got her admitted to Phnom Penh's Sen Sok hospital, where doctors are fighting to save her.

Soth Rey is suffering from pneumonic septicaemia and is chronically malnourished because she can't eat. Doctors have never seen such a serious case of necrosis.

The fundraising campaign aims to raise $US30,000 for her hospital bills and reconstructive surgery, which would probably have to be done in Bangkok.

Yulia Khouri, a resident of Phnom Penh, fought back tears in a Facebook post as she told how Soth Rey is refusing to give up, describing her as a "young, beautiful, vibrant person".

"The amount of goodwill is incredible, but there have been some crooks trying to take advantage of this," Ms Khouri, a Canadian, told the Phnom Penh Post, a reference to dubious websites that have replicated Just Giving's call for donations.

Ian Matela, one of Soth Rey's doctors, said if she does survive there will be a very long recovery process. "This is just the beginning," he said.