People with food allergies are among the worst served by doctors, according to a large-scale review of research into the condition.

The review discovered that patients were being misdiagnosed and allergy tests were giving misleading results. Up to 30 per cent of people claim to have an allergy to certain foods but in a blind-test fewer than 10 per cent actually have one.

Some of the well known allergy avoidance principles such as breast-fed babies have fewer allergies or avoiding feeding a baby eggs during their first year have been found to have little evidence to support them.

The review also found that adults are eliminating foods from their diet without evidence based on a suspicion the food is causing an allergic reaction. Parents are also stopping their children from eating certain foods even though most will grow out of an allergy.

The findings come as the US National Institute of Allergy and Infectious Diseases begins the first stage of a project that it hopes will organise the chaos that surrounds food allergy testing.

Common food allergies are to cow’s milk, eggs, peanuts, fish and shellfish. However, the review found that 3.5 per cent of people who reported an allergy to cow’s milk, when tested the figure dropped to 0.9 per cent.

Shellfish allergies dropped by nearly half from 1.1 per cent of reports of an allergy to tests showing only 0.6 per cent who were actually allergic.

The one allergy that achieved consistency in reported figures of a reaction to positive testing was for peanuts.

Researchers believe part of the problem is people confusing food allergies with food intolerances. An allergy is a response by the immune system to certain foods which triggers a symptom such as a skin rash or in extreme cases anaphylactic shock.

Food intolerances can be triggered by a substance in the food or a psychological response caused by association between food and illness.

Pamela Ewan, consultant allergist at Addenbrooke’s Hospital, Cambridge, spoke about the problem in The Independent.

“In the UK, 4 per cent of adults and 5-6 per cent of children are thought to have a food allergy. Many more believe they have one – up to 30 per cent. Some are completely wrong. But people can have a real problem with foods even though it is not an allergy.”

“The chaos is massive in the UK. Doctors untrained in allergy are having to pick up cases in gastroenterology clinics, asthma clinics, dermatology clinics. They send off a test and it comes back positive for IgE antibodies. But it has to be interpreted. A test without good quality information is misleading.”

“People get the wrong advice because the tests are not understood. Having the test in the wrong hands without knowing what it means, causes chaos.”

“The key problem is that we haven’t got enough people who understand allergy. There are 30 consultants nationwide and just 12 training posts, not even enough to replace those who are leaving.”

Learn more about allergy intolerance testing in this article