Practically unheard of just a decade ago, allergy rates among children have soared over recent years to the point where two in every five ACT children suffer from some sort of allergy, asthma or skin-related condition. Largely a mystery to the medical community, Australians are reporting allergy rates higher than any other country.

Staff at the YMCA Early Learning Centre in Jamison have created a protective environment to keep four-year-old Alexandra Hasda-Hall safe from the allergens that could make her ill.

But it's also the safety of teenagers and young adults, such as 20-year-old Brendon Clarke-Pepper, who have severe allergies, that is beginning to concern food allergy experts.

The four-year-old has a sesame allergy and is also intolerant to several other foods and products, including tomatoes, eggs and ingredients in most sunscreens.

Her childcare centre is nut-free and staff have individual action plans in place for children who are at risk of severe allergic reactions.

But young adults with food allergies have to take responsibility for their own health and are the group at greatest risk of the anaphylactic reactions that claim about 10 lives in Australia each year.

Mr Clarke-Pepper, of Braddon, discovered he was allergic to fermented foods earlier this year after he suffered anaphylaxis when consuming miso soup he had cooked for the first time.

''I started eating and 20 minutes later I couldn't breath and my partner had to call an ambulance for me,'' he said.

The rapid arrival of paramedics and a shot of adrenalin saved Mr Clarke-Pepper's life.

Until the early 1990s, Robert Loblay, an immunologist who heads the allergy unit at Royal Prince Alfred Hospital in Sydney, saw only two or three patients each month with food allergies.

That changed suddenly and doctors still do not know why.

Ten years ago there was only a handful of sufferers, today an estimated 40 per cent of children have an allergy of some sort such as asthma or dermatitis.

''By the end of the 1990s or early 2000s they were flooding in,'' Dr Loblay said.

About 2 per cent of Australians are believed to have food allergies.

Dr Loblay said the first wave of young children diagnosed with food allergies were now young adults, entering the workforce and leaving the protective environment their families created at home.

''The teens and early adults are the ones who are most at risk of having a fatal reaction,'' he said. ''I think a lot of our future efforts are going to have to be directed at the young adults and the things they do.''

Dr Loblay said many young adults with food allergies had suffered from reactions in the past and tried to protect themselves. But they could be exposed to an allergen because somebody incorrectly told them a dish was free of a particular food.

''Or, maybe they didn't tell anyone they've got an allergy because they didn't want to seem a dork, or they go out without their EpiPen because they don't want to seem a dork and carry a purse or put it in their pocket,'' Dr Loblay said.

Maria Said, president of allergy support and advocacy group, Anaphylaxis Australia, said young people with severe allergies needed support and appropriate specialist medical care to ensure that they knew how to look after themselves.

''These people need to be responsible for themselves - but there's a community and workplace responsibility as well,'' she said. ''If these people are going to lead normal lives they need a workplace, a community, a school that is aware of food allergy and supports some of their needs.

''I'm not talking about banning foods, or making free claims or anything like that but about an acknowledgment and teaching food services how they respond to people with allergy.''

Dr Loblay said while it was unclear why the prevalence of food allergies was increasing it was interesting to note it had occurred at the same time as an increase in obesity rates.

''There's probably a different pattern of eating that's going on in the community generally which might be predisposing to both of these phenomena,'' he said.

''Particularly a lot more snacking, a lot more snack foods, a lot more pre-prepared foods, a lot more peanuts and other nuts in snack foods.''