Dr Jonathan North, a consultant immunologist in Birmingham, said: "We used to say that 15% of the population had an allergy of some sort, now the figure is nearer 40%.
"As well as the well-documented increase in prevalence, the proportion of complex/multiple allergy cases is increasing."
The reasons for the rise are not fully understood.
"One of the theories, which I think makes sense as regards food allergy, is that we now have a far wider range of foods available and children are being exposed at a much younger age," said Dr North.
Symptoms more severe
Dr Shuaib Nasser, a consultant in allergy for the Cambridge University NHS Trust, has also noted the growth in multiple allergies and is concerned about the increasing severity of allergy symptoms, which can be fatal.
For asthma and hay fever patients, Dr Nasser says the period of suffering is also getting longer.
"We may think of some allergies as being simply inconvenient but there are patients who die from allergic disorders.
"Hay fever is not just a runny nose. Patients develop asthma and are admitted into hospital."
I find it is unusual for anyone to have a nut allergy without having eczema
Dr Shuaib Nasser, allergies expert
Dr Nasser has been running an investigation into asthma deaths.
"We have found that asthma deaths peak in July and August.
"We know that the reason they peak is due to environmental allergens, fungal spore levels."
Climate a factor
According to Dr Nasser, climate change is largely to blame.
"Global warming is causing an increase in fungal spore levels as well as pollen, so this is something we are going to see more of. The season is also starting earlier and finishing later.
"Many of these deaths occur in children. They are mostly completely preventable if they are diagnosed properly."
Consultant allergist Dr Shuaib Nasser explains how certain allergies tend to be grouped together.
Chris Doyle, a senior nurse who specialises in asthma and allergy at Alder Hey Children's Hospital in Liverpool, says there is often a pattern to the allergies affecting the youngsters she sees.
"We have seen a significant rise in the number of allergy referrals. Often these children have multiple allergy problems.
"The initial referral from the GP may go something like this: 'Please see this child who has recently had an allergic reaction to a peanut'.
"Then when we do see the child, they are also found to have eczema, asthma and hay fever and often food allergies as well."
Kirsty Speed, a 27-year-old dancing teacher from Cambridge, is a living example of Nurse Doyle's list.
Having suffered from eczema as a baby, she developed a peanut allergy from the age of two.
The extent of her problems was not properly diagnosed until she was aged 15.
"I hated being the odd one out and making my allergies an issue in my life," she said.
"I often had to sit out of dance classes when I was a child to use the inhaler. If I was dancing in a dusty room, it would bring on an even worse asthma attack.
"Then when I was about four it was realized that I was allergic to my lovely pet dog.
"It was heart wrenching to have to take it back to the animal sanctuary."
Dr Nasser says the rise in multiple allergies should be seen within the context of the overall rise in allergies.
The UK has one of the highest diagnosed allergy rates in the world.
"The number of people with more severe allergies is increasing and if you have a severe allergy you are more likely to have multiple allergies".
He points to the rise in eczema as being significant. The number of cases in England rose by 40% in four years according to a study published last month.
One theory for this increase in eczema - which causes severe scaling and breaking of the skin - is that the overuse of soaps and detergents is robbing the skin of its natural nutrients.
Eczema is now being seen as a "gateway" which can enable other allergies to develop.
Dr Nasser explains that the broken skin can allow allergens such as peanuts to enter the unprotected body, prompting the immune system to react as if the peanut was an enemy invader.
"Consequently I find it is unusual for anyone to have a nut allergy without having eczema. It is my belief that nut allergy and most food allergies are often a result of the body becoming sensitised to them through the skin." he said.
Dr Nasser says the reasons for the growth in allergies are several and complex.
He cites the hygiene hypothesis as one that is widely supported by the medical profession.
"The UK is a developed society and allergies affect westernised countries. If a country passes from a rural to an urban society then the existence of allergies escalates.
"The hygiene hypotheses is that in a developed society we avoid exposure to bacterial infection at an early age. This is unlike rural environments", he explains.
As Dr Nasser said: "Some say modern life is making us allergic."
On the BBC News website tomorrow: How fruit and vegetable allergies could be the new epidemic.
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