A homeopath, Thomas Sam, 42, and his wife, Manju Sam, 36, are standing trial in the NSW Supreme Court charged with manslaughter by gross criminal negligence after they allegedly resisted the advice of nurses and a doctor to send her to a skin specialist.

Instead Gloria Thomas, who was born in perfect health in July 2001, allegedly died with malnutrition and eczema so severe that her skin broke every time her parents removed her clothes and nappy.

The court heard that Gloria was above average weight, height and head circumference until she was four months old, but lost 20 per cent of her body weight in the last five months of her life after a nurse first identified her eczema and advised her parents to send her to a skin specialist.

The Crown prosecutor, Mark Tedeschi, QC, told the court they sat on this advice for two months and then saw a general practitioner who was so concerned by her condition that he told them to see a skin specialist immediately. But again, they demurred.

"The Crown case is that from this point on, for the next five months of her life until her death … Gloria's eczema played a devastating role in her overall health and it is asserted by the Crown that both her parents knew this and discussed it with each other," Mr Tedeschi said.

"Over time the eczema caused her skin to become thinner and weaker and the constant breaking of the skin allowed infections to enter her body."

The parents, who each had university degrees and postgraduate qualifications, instead sought help from other homeopaths and natural medicine practitioners, Mr Tedeschi said.

On the few occasions that they did follow conventional medical advice, Gloria would improve, but they would soon revert to homeopathic remedies and she would continue to deteriorate.