Having an allergy can cause great anxiety

But while these rather soggy symptoms are easily dismissed by those who can get through a summer without reaching for the antihistamine tablets, for sufferers an allergy to pollen can make their life a misery.

Although allergies are often written off as a trait of our cosseted, too-clean society, it is believed that a quarter of the UK's population suffer from some sort of allergic reaction, be it to dust mites, cut grass or pet hair. Then there are those whose allergic reactions can ultimately lead to anaphylactic shock and, potentially, death.

So as National Allergy Week launches, we take a look at the most common allergies and the latest science behind the drive to find solutions to the epidemic.

POLLEN AND DUST

An allergy to pollen is commonly known as hayfever, but also goes by the name allergic rhinitis as it involves the inflammation of the nose, eyes or sinuses.

It affects about 28 per cent of the population and it is thought sufferers could double to 32 million by 2030.

It is caused when the body mistakenly makes an allergic antibody to pollen, house dust mites, cat, dog or hair, and releases chemicals from cells in the nasal passages, eyes or airways which cause inflammation and irritation. One in ten sufferers find their symptoms affect their ability to drive, do their job or even sleep.

Grass pollen is the most common allergen, but some people are allergic to tree, weed and shrub pollens. Symptoms that continue all year round are more related to indoor allergens, such as house dust mites, pets and indoor moulds.

Already this year's hayfever season is being predicted as a potential nightmare for sufferers as the cold winter has delayed the start of the spring allergy onslaught. Forecasters predict warm, dry weather instead of the usual April showers towards the end of this month, sending the tree pollen count suddenly soaring just before the grass pollen season begins.

Doctors are already urging sufferers to start taking preventative medication to control their symptoms, while nationwide medical charity Allergy UK has changed the date of its National Allergy Week to April 11-17 to reflect this expected level of hayfever.

The charity has also revealed that hayfever sufferers are being put at risk of developing asthma because of a lack of allergy specialists able to deliver the treatments or to train GPs in allergy diagnosis and management.

The charity's research has also shown that with 38 per cent of teenagers suffering from hayfever, many of them will drop at least one grade in their examinations due to their allergy.

Professor Aziz Sheikh, chairman of Edinburgh University's Allergy and Respiratory Research Group, has suggested that exams should be moved to winter months to help teenage hayfever sufferers.

He adds that it's vital sufferers get the right medication. He says: "We know that in people with allergic rhinitis there's a significant impairment in quality of life and getting the right treatment is important," he says.

"There's still under-diagnosis of this problem so there needs to be more clinician awareness. The majority of patients are put on an antihistamine which isn't always the most effective treatment."

If the allergy is so severe that antihistamine tablets and nasal sprays are not enough, then there's always immunotherapy to desensitise the body to the allergen.

To date, the most effective treatment is a course of injections which can have long-lasting benefits for allergy to grass pollens, tree pollens, house dust mite allergy and allergy to pets. A tablet form is only available for grass pollen allergy.

However, as immunotherapy is so intensive and time consuming, it is only for those with extreme symptoms and requires a referral to a specialist allergy clinic by a GP.

FOODS

An allergy to a food, be it milk, egg, nuts, sesame or seafood, is vastly different from a "sensitivity" or an "intolerance", both of which, while unpleasant, are not potentially fatal. True food allergy, which can result in anaphylactic shock, affects more than one million people in the UK.

It is generally a protein in a particular food which causes the problem and the best approach is total avoidance.

In Edinburgh, there has been a massive amount of research into food allergies - nuts, in particular, which affects 1.3 per cent of the population.

A recent study from Edinburgh University, published in the Journal of Allergy and Clinical Immunology earlier this year, claimed that peanut allergy was more prevalent in boys and in more affluent families.

Dr Daniel Kotz, who led the research says: "Having a serious allergy like this can cause great anxiety and stress to those affected. We now need more research to help explain why the condition occurs relatively more often in boys and affluent people."

A Dundee University report recently linked a mutation in the gene filaggrin to nut allergy. It was previously linked with asthma and eczema.

Peanut allergy is usually lifelong, though there is research under way at Edinburgh's Sick Kids hospital into desensitisation.

If sufferers do come into contact with a peanut, then an anaphylactic shock can result, which can include swelling of lips, tongue and face, nausea, swelling of the larynx, shortness of breath and loss of consciousness.

Currently, the only accepted therapy for food allergy is strict avoidance of the offending food, but sufferers must always carry antihistamine and EpiPen (adrenaline injectors) in case of an emergency.

BEE AND WASP STINGS

Anyone can become allergic to bee and wasp stings but those most likely to are beekeepers or people who work in gardens. However, it is unusual to be allergic to both insects.

Deaths from stings are extremely rare and mainly affect older people. Most people survive sting allergy reactions, even if they receive no effective treatment, although sufferers are advised to carry injectable adrenaline.

LATEX

Skin problems associated with rubber contact have been known for many years. The most common is irritant contact dermatitis which can progress to a low-grade eczema, but allergy to the chemicals used to process rubber produces allergic contact dermatitis which tends to produce blistering and weeping, as well as redness and itching.

This type of allergic reaction is the same type that occurs in hayfever, asthma and peanut allergy. It can vary in severity from a mild rash on contact to severe anaphylaxis with respiratory symptoms and collapse.

More than six per cent of the population are now allergic to latex and ten per cent of health personnel who wear rubber gloves regularly suffer the symptoms. Avoidance of latex is the best advice, though EpiPens can also be prescribed.