From peanuts to shellfish... Why are so many adults suddenly getting allergies?
Danger: Edwina Galloway can no longer eat peanuts after developing an allergy to the food aged 38
When Edwina Galloway started to feel a strange knot in her throat after eating some peanuts, she tried to ease it by drinking tea.
But within minutes her throat was constricting and she was
struggling to breathe. Her husband bundled her into their car and
rushed her to hospital.
Fortunately, it was only a mile from their home in Sevenoaks, Kent; had it been much further, Edwina could have died.
'By the time I got there, I was shivering and shaking as my body was going into shock,' says Edwina, 48, who runs her own administration business. 'It was terribly frightening.'
Edwina was suffering from anaphylactic shock - an allergic reaction which causes puffy lips and eyes, other symptoms such as vomiting and breathing difficulties as the air passages swell. Untreated, it can prove fatal within minutes.
Edwina was immediately given antihistamine, which eased her symptoms. She later underwent tests to see what had brought on such a violent reaction; the results couldn't have been more surprising.
'I was told I'd developed an allergy to peanuts and hazelnuts,' Edwina recalls.
'It was a real shock, as there is no history of allergies in my family, and I certainly had never had an allergy before.
'In fact, my husband is a vegetarian and so nut roast had been a staple of our diet. This allergy just came on out of the blue.
'Now I have to carry an adrenaline jab with me at all times in case I have a really bad reaction.
'Luckily, that hasn't happened yet, but the allergy has changed my life. I have to be incredibly careful about what I eat because it takes only a trace of nut to set me off.
'I went to a friend's house for lunch a year ago, and although she was very careful to prepare food without nuts there must have been a tiny hint somewhere because I took a mouthful and blotches started to come up on my face.'
Over the past decade there has been a huge rise in the number of Britons suffering from hay-fever and eczema as a result of allergies.
As many as one in four people is affected, and the incidence continues to rise. A report published last month found the number of children with allergies had tripled in the past decade to 40 per cent.
Yet it's not just children who are affected. The charity Allergy UK says that, increasingly, middle-aged and older people are developing allergies for the first time. Like Edwina, they suddenly suffer a reaction to something that for decades did them no harm.
'In the case of food allergies and anaphylaxis, I now see more adults than children - we are inundated with cases,' says Andrew Williams, a consultant nurse who runs an adult allergy clinic at Homerton Hospital in London. 'Allergic rhinitis and asthma are also becoming more common among adults.'
Many women suddenly develop an allergy during the menopause, says Moira Austin, helpline manager at Anaphylaxis Campaign.
'Another common time seems to be after having been in hospital.'
Often the allergies involve foods such as nuts or shellfish. 'The reactions tend to come on quickly and severely,' says Moira Austin. 'This can be very surprising and very frightening - and potentially fatal.'
An allergy occurs when the body over-reacts to the presence of something harmless and produces antibodies and chemicals such as histamine in response.
It is the body's way of trying to get rid of the perceived invader as rapidly as possible.
An anaphylactic reaction, such as the one Edwina had, occurs when the body produces a huge amount of histamine from all of the body's cells, not just localised ones, as happens in a milder reaction.
Even just a small trace of peanut in a meal can trigger anaphylactic shock in Edwina
The large amount of histamine causes blood vessels and tubes in the lungs to swell, leading to severely reduced blood pressure and breathing problems.
Typically, allergies start in childhood, when the immature immune system is more likely to over-react, but often improve in time. So why are adults now being affected for the first time?
'No one truly understands what prompts allergies in later life,' says Isobel Skypala, a specialist allergy dietician at London's Royal Brompton Hospital.
'It may be that stress is partly to blame, as this can send the immune system into overdrive. Hormonal fluctuations also have an effect on the severity of allergies, and food allergies do seem to be more common in women than men.
'In the case of food allergies, it may be partly due to the wide range of foods available these days. But we are also seeing more severe reactions in adults to plant foods that have long been part of the UK diet, such as lettuce,' she says.
Adults who already have an allergy are also increasingly developing further allergies ('multiple allergies'). Another possible cause for this late onset of allergy is our modern lifestyles.
'Our immune system doesn't just need stimulation in early life, it needs stimulation all the time to stop it over-reacting,' says Professor Graham Rook, a microbiologist from University College Hospital, London. 'However, with our current lifestyles, our immune systems are not being challenged enough.
'For example, in years gone by we would have had regular exposure to bacteria found in muddy water, and these bacteria would also have been found on unwashed fruit and vegetables.
'Throughout evolution, all animals and humans will have consumed large numbers of these bacteria daily. Now we drink sanitised water and scrubbed fruit and veg, so we have no contact with them.'
Indeed, animal studies have shown that regular exposure to such bacteria can reverse eczema, for instance.
'There are also trials running with various parasitic worms as treatments for allergies, because these are also involved in regulating the immune system,' explains Professor Rook. 'Again, these have been progressively depleted from humans in rich countries.'
High use of antibiotics in children may also increase the risk of allergy later in life, he adds.
'This can cause profound and long-lasting changes to the balance of bacteria found naturally in the gut. These are known, like the muddy water bacteria, to be involved in regulation of the immune system. So it is possible that antibiotic use is contributing to the incidence of allergies.'
A lack of vitamin D as a result of our paranoia about skin cancer could be to blame, too. 'Vitamin D is vital for turning on parts of the immune system. How large the effect vitamin D deficiency has on allergic disorders no one yet knows, but it is an interesting area.'
What is clear is that many adults even in their 60s are developing allergies such as hay-fever.
According to Allergy UK, this might be because pollen is being released earlier in the year, adding to the overall amount of pollen in the atmosphere. Another theory is that diesel fumes are mixing with pollen to make it more allergenic.
Another late onset allergy is hay-fever, possibly due to pollen being released earlier in the year
One such late onset patient is former policeman Peter Simmons, who developed hay-fever five years ago at the age of 61.
'Allergies had never been on my radar,' he says. 'Then, in the spring of 2003, I developed really itchy eyes. But it cleared up after a few months and I thought no more about it. The next spring it happened again, but this time my nose ran all the time, too. It really stopped me getting on with things.'
He was persuaded to take an allergy test, and was diagnosed with an allergy to birch.
Sadly, for adults who do develop an allergy, getting help can be hard due to a scarcity of allergy specialists.
Yet treatments including desensitisation - administering tiny amounts of the allergen which stops the immune system overreacting to it - can, in some cases, cure the allergy altogether.
Even just getting a proper diagnosis, so you can take steps to avoid what you are allergic to, can make a big difference to your life, says Dr Pam Ewan, consultant allergist at Addenbrooke's Hospital, Cambridge.
'We have found that by giving better management for allergies at our allergy clinic, we can reduce the number of allergic reactions by ten per cent,' she says.
• Allergy UK, allergyuk.org, 01322 619898. Anaphylaxis.org.uk, 01252 542029.
Medical miscellany: Why do we burp?
We usually burp because we've swallowed air during eating or drinking, says Dr Peter Fairclough, a consultant gastroenterologist at The London Clinic.
'We know this because a U.S. doctor spent years studying belching and discovered burps contain mostly nitrogen, which the body cannot make.
'Thus, he concluded, this nitrogen came from outside air.'
The reason some people burp more loudly than others is that they have fewer social inhibitions, he explains - there is no anatomical reason for it.
Dr Fairclough adds that not all the air we swallow will reappear as a burp; about half of the gas that emerges out the other end is nitrogen from swallowed air.
Spend or save? Snoring
Can you cut costs on healthcare products? We ask the experts.
Mr Hugh Wheatley is a consultant ear, nose and throat surgeon at the Nuffield Hospital, Cheltenham, and the Winfield Hospital, Gloucester. This is what he says:
Snoring is usually caused by breathing through the mouth - the air vibrates on the tissues at the back.
The strips help by expanding the nasal passages, which encourages people to breathe through the nose instead.
The spray contains essential oils supposed to help tone the tissues, making them less inclined to vibrate.
I'd go for the cheaper product as these strips can be effective; I'm not convinced the spray would work for long as it's likely to be washed away by saliva.
Anything bought without an expert opinion will be trial and error, so it's better to start with the cheaper one.