Some pure ingredients from food sources in skin care products can still pose a problem for people with severe food allergies.

"Surprisingly, some of these products contain foods which are known to cause allergy," Professor Robyn O'Hehir, Director of Allergy, Immunology and Respiratory Medicine said. "Goat's milk, cow's milk, nut oils and oats are common ingredients in 'natural' cosmetics." The study, in The Journal of Allergy and Clinical Immunology: In Practice, demonstrated a link between cosmetic use and food allergies.

"While unlikely to be a problem for most people, application of these to broken or eczematous skin may lead to a severe allergic reaction when the food is next eaten," Professor O'Hehir said. "To ensure allergies don't develop, if you have eczema, it's important to use skin care that is bland and avoid agents capable of sensitization, especially food."