YOUR HEALTH:New evidence points to a 'medical gap' in the area of food allergies, with many people self-diagnosing or taking the wrong action

EARLIER THIS month, The New York Timesreported on a study that cast doubt on the extent of true food allergies.

The story centred on a study that combed through more than 12,000 published studies on food allergies between 1998 and 2009 and found that 72 met the selection standards.

From that relative handful, it wasn’t clear whether the prevalence of food allergies had been increasing, and one of the mainstays of treating food allergies – eliminating the offending food from the diet – rarely featured in the published papers.

"This systematic review of food allergies found that the evidence on the prevalence, diagnosis, management and prevention of food allergies is voluminous, diffuse and critically limited by the lack of uniformity for the diagnosis of a food allergy, severely limiting conclusions about best practices for management and prevention," write the authors of the report in the Journal of the American Medical Association.

So when even the scientific literature hasn’t a clear line, how easy is it to know whether a person has a genuine food allergy or intolerance? And do people sometimes think they have a food allergy when they don’t?

Prof Jonathan Hourihane, professor of paediatrics and child health at University College Cork, sees many cases of foods being restricted from children’s diets on the basis of a supposed or self-diagnosed allergy.

“It’s our experience that children are often off things they don’t need to be off when they come to see an allergist,” he says, citing eczema as an example. “You can have eczema without food allergy, so the fact that you have eczema doesn’t mean you are allergic to a food that you can’t identify. People come to see us on diets where they are eliminating four or five foods and the child still has eczema – but it can’t be those foods because they are not on them.”

However, there are other cases where the reaction to a particular food is rapid and potentially fatal, notes Hourihane. “Anaphalaxis is a severe, life-threatening allergic reaction that can cause death,” he says, noting that food allergies account for about a quarter of anaphylactic reactions.

“And in a circumstance where anaphylaxis is likely or possible, there’s no reason not to treat it as anaphylaxis. Just like if you think there might be a fire in your kitchen there’s no reason not to get out the fire extinguisher – if there isn’t a fire then all you have is some foam around, but if you miss it, your house burns down.

“Anyone who has had anaphylaxis needs to have emergency treatment available.”

In general, Hourihane sees a “medical gap” in the area of food allergies, which affect an estimated 2 per cent of adults and about 6 per cent of preschool children, and he would like to see better awareness among primary caregivers as well as more services for those in need.

“If we had enough medical allergists to take in all these patients, we would be in a better state,” he says. “Once people get under the care of an allergist their quality of life usually improves, their chances of having a severe reaction usually decreases and their awareness of what to do and their self-confidence improves.”

That gap is echoed by Dr Brendan Fitzpatrick, a medical doctor at the Slievemore Clinic in Dublin who has an interest in complementary approaches. He suggests people may have a tendency to self-diagnose.

In cases where they do come for treatment, however, he would like to see more information being gathered when determining whether a person has a food sensitivity.

“Traditionally within the medical profession, a food allergy has a fairly rapid onset, and you do skin scratch or blood tests and it will generally come up,” he says. “But food can affect you in other ways as well.”

In particular he cites digestive irritants such as coffee and curry, ill effects from yeast, and enzyme deficiencies that make it hard to digest milk.

Fitzpatrick believes that in some cases looking beyond the immune-response definition could help patients get answers if an allergy doesn’t show up in testing.

“The medical profession tries to limit it to IgE , which makes it more scientific, but in many ways it deprives people of access to treatment or consideration of what foods can do by other mechanisms,” he says. “It might not be a real allergy, but it’s causing significant morbidity or harm to the person.”

By eliminating the food from the diet and later re-introducing it, and by looking at the person’s history, Fitzpatrick aims to rule particular foods in or out as being a problem if an allergy hasn’t shown up through the skin scratch or blood tests.

“The medical profession has been slow to recognise how important food intolerance is, and there’s a perception that it’s over-diagnosed in other circles. But it allows patients to move on if it’s quite clear that diet isn’t playing a part in it,” he says.

SISTER ACT: RAISING AWARENESS OF ALLERGIES

When she was two years old, Edel Connolly bit into a peanut and had an anaphylactic reaction. Then, when she was about seven, she discovered that peaches triggered the same response.

Now nine, Edel and her 18-year-old sister Louise have set up a website to help raise awareness of anaphylaxis, a severe and rapid allergic reaction during which symptoms can range from hives on the skin to swelling of the mouth and throat.

“Other people don’t really know that much about anaphylaxis,” says Edel. “Sometimes they wouldn’t know about nuts and peaches, and they can just walk up to you with them.”

To help avoid exposure to the offending foods, Edel tells people about her allergy, her school has a policy of not sharing lunch, and she brings medication with her everywhere just in case.

To build the website – beallergyaware.com – the girls put together information for various groups, including children and teenagers and people who are travelling or catering, and they have already won a 2009 Allergy N I Young Person of the Year Award and an Aramark Healthcare Innovation Award for their work.

The message is to take allergies seriously and to be aware of those who have them, says Louise.

“If you know anyone with allergies then make sure you know the action plan if they have an allergic reaction.”

FOOD ALLERGY OR INTOLERANCE?

In childhood, milk, egg and peanuts are the “big three” for food allergies, where the body basically mistakes a food component as a threat and mounts a rapid immune response to it.

Other usual suspects include fish and shellfish, tree nuts and seeds, soya and wheat. Many people outgrow childhood food allergies, but in some cases they persist into adulthood.

On the other hand, food intolerance is where a person cannot break down a food component properly, or it irritates their digestive system. It may arise if a person has been exposed to too much of a particular food, and it does not involve the immune response seen in allergy.

The Irish Allergy Fair will take place at the RDS, Dublin 4 from May 28th to 30th 2010. Visit rds.ie for more details