They are not a problem that is going to go away, either. As Muriel Stevens of the British Allergy Foundation (BAF) - a registered charity formed in 1991 by a group of medical specialists to increase awareness, prevention and treatment of allergies - says: "We are definitely becoming more allergic. This isn't just here in Britain, although in the UK we have one of the highest rates of allergy. It's true of most European countries."
She cites a recent report from a study in Germany which compared allergy levels in the east and west both before and after the fall of the Berlin Wall. "Allergy levels shot through the roof in East Germany when the wall came down and the Western way of life came into the East."
So what is it about our way of life that causes so many problems, and what can the canny shopper do about it? Muriel Stevens has at least one suggestion. "For a start we all like to be nice and warm. We have thick carpets and double glazing and central heating blasting away, and the house dust mite says, `Whoopee, this is a lovely environment to live in'." And, unfortunately, house dust mite allergies lead to rhinitis and ultimately to asthma.
Luckily, this does not mean that you have to chuck out your carpets and turn off the heating. There are other ways of coping with the dust mite problem.
You can buy sprays that can be used on carpets and soft furnishings, though not on bedding. Pillows and duvets need to be made of the right materials so they can be washed at the hotter temperatures - higher than 60C - that kill the dust mite.
Sadly, it is not just the house dust mite that can spoil your night's sleep. Niki Kortvelyessy, whose shop World of Difference caters for anyone wanting a more environmentally friendly lifestyle, points out that one allergy not widely talked about is to formaldehyde.
It is used in many household products: carpets, chipboard furniture and in treating cotton bedding to make it non-iron and flame-resistant. "Apparently it never stops exuding," says Niki. "Obviously it's worse when new, but even years and years later it still exudes the fumes." As a result, one of WoD's best-selling ranges is of pure cotton, untreated bed linen.
The British Allergy Foundation also recommends people make sure they get the correct vacuum cleaner, and vacuum curtains and soft furnishings once a fortnight. To help you choose the right cleaner, they have set up a scheme called the Seal of Approval, which looks like a leaf in a circle and is clearly marked on the packaging of selected products. "We test things like vacuum cleaners, air filters, ventilation systems and carpeting to see how they can help in allergen avoidance," says Muriel Stevens. "With vacuum cleaners, for instance, we test whether they suck up dust mites and also whether they retain them."
One useful "one-stop shop" for allergy sufferers is The Healthy House, a mail-order company that concentrates on items you cannot find in the high street.
Maxima Skelton says she and her husband set up the company because their own children suffered so many allergies, "and we had problems finding the right products". Now they sell a full range of goods, from cotton gloves for children with eczema to special paints and varnishes, air filters and detergent-free clothes cleaners.
But what if it is the kitchen and not the bedroom that is giving you cause for concern. There seems little doubt that what we eat is giving increasing cause for concern as our overloaded immune systems start biting back. "Food is a growing nightmare," admits BAF's Muriel Stevens. "You no sooner think that there can't be anything else coming out of the woodwork than it does."
Clare Marriage, marketing director for specialist flour mill Doves Farm Foods, agrees: "For instance, we get a lot of letters from people who tell us that they can't eat wheat or gluten and they buy a variety of products from us. There are gluten-free flours you can buy on prescription, and those tend to be made from wheat that has been treated in a factory to remove the gluten content. The kind of gluten-free flours that we make and sell are all from non-wheat sources - that is, from grains or beans that are naturally without gluten."
The whole subject of food allergies is vast, and the biggest problem people face is finding out what they can eat, where to buy it and how to cook with it. This is particularly true for anyone whose allergy is self-diagnosed, rather than being something their GP has spotted.
Clare Marriage recommends a visit to a good independent health food shop, "because by and large they have a good selection of products that are suitable for people who are thinking about their diets. "More than that, an independent health food store has very often got somebody or several people working there who have the time to talk to an individual and to try and make helpful and relevant suggestions."
Otherwise, it is up to each individual to find out as much as they can about their own allergy, or allergies. As well as keeping an eye on health articles in the press, other sources of information include BAF, which can send out lists of recommended products, help with diagnosis, point you towards your nearest allergy clinic, and generally give useful advice.
In shops, you need to be as demanding as possible to make sure you end up with the right product. As Muriel Stevens points out, "It isn't any good being nice and polite. If you're an allergy sufferer, your life can be in danger."
She cites a recent shopping trip where she went to buy a vacuum cleaner suitable for asthma and was offered the least suitable one on the market. "If I had truly been asthmatic, that cleaner would have caused me serious problems."
In the end, she pointed out the Seal of Approval on the box of another machine, something the shop assistant admitted he had never noticed before.
The message is clear: do your own homework.
Doo't be afraid to ask questions, do as much research as possible, think carefully about what you are prepared to do to tackle your problems. If not, you may well find a whole new meaning to the phrase "rash decision".
British Allergy Foundation, Deepdene House, 30 Bellegrove Road, Welling, Kent DA16 3PY (0181-303 8525); Doves Farm Foods, Hungerford, Berkshire (01488 684880); The Healthy House, Cold Harbour, Ruscombe, Stroud, Gloucestershire GL6 6DA (01453 752216); World of Difference, Woburn Walk, London, WC1H 0JL (0171-387 2363), 11am-6pm Mon-Sat