In a letter published in the Medical Journal of Australia, Canberra allergy and immunology specialist Raymond Mullins has outlined details of the case and speculated that the soap may have ''sensitised'' the woman to allergens.

The unidentified woman began using various brands of goat milk soap in 2009 to treat dry skin and mild eczema. The following year she experienced an itchy mouth when eating goat cheese and then hives after using goat milk moisturiser.

In 2011, she suffered tongue and throat swelling after eating goat, sheep and fetta cheeses.

Earlier this year, she became seriously ill and required treatment with adrenalin after accidentally eating goat cheese.

''Unfortunately, goat milk soap has the potential, as does any soap, to aggravate the dryness of a non-intact skin barrier,'' Dr Mullins wrote.

''Of specific interest, is whether topical exposure to food allergin in goat milk products may have sensitised the patient to later oral ingestion.''

Dr Mullins told The Canberra Times that the case was unusual and there was unlikely to be an outbreak of allergies in people who used soaps which contained goat milk.

But he said he would advise eczema sufferers to use moisturisers that contained non-food products.

''Avoid soap of all types - including goat milk soap - and if you have a choice of using a moisturiser that contains food, don't,'' he said

Dr Mullins said people with eczema had particularly dry skin and a protein mutation could cause skin to fall apart. This made it important to use a moisturiser.

''Essentially use you the cheapest moisturiser that works for you, but use it all the time.''