An oral immunotherapy can treat egg allergy, allowing patients to safely incorporate the highly nutritious food into their diet, scientists say.

For a study, participants completed up to four years of egg oral immunotherapy (eOIT) treatment.

According to researchers from University of North Carolina (UNC) in the US, certain participants were able to safely incorporate egg into their diet for five years.

"Egg allergy is one of the most common food allergies and usually appears in early childhood. It has significant risk for severe allergic reactions and negatively affects quality of life for children with the allergy," said Edwin Kim, assistant professor at the UNC.

"While the allergy does seem to go away with age, it can last into the second decade of life for most people. Any treatment that can allow the introduction of egg into the diet of someone with egg allergy provides nutritional benefits and peace of mind for the patient and their family," said Kim.

The trial began with either eOIT or a placebo for 55 patients aged 5-11 who were allergic to egg. The treatments were randomised -- 40 participants received eOIT and 15 received the placebo.

The treatments lasted up to four years, during which patients were tested for their sensitivity to egg.

Those who were considered desensitised --requiring a higher quantity of egg to cause an allergic reaction -- could eat 10 grams, or about two teaspoons, of pure egg without reaction.

Desensitised patients then stopped eOIT and were tested for sensitivity again. Those who did not have a reaction were considered sustained unresponsiveness (SU).

After completing eOIT, concentrated egg (scrambled, fried or boiled egg) and/or baked egg (eggs incorporated into something like a cake) were recommended to be added into the patients' diet.

For five years following the allergy treatment, patients were asked to report how much egg they ate, in what form they ate it, how often they ate it and how they felt afterward.

At the end of eOIT, 50 per cent of patients were classified with SU, 28 per cent of patients were classified as desensitised (without SU) and 22 percent as not desensitised.

Of SU-classified patients, all were able to eat both baked and concentrated egg.