Summer Health - Allergies

More and more people are developing allergies. Well-known allergic diseases include hay fever and eczema, and there is an allergic aspect to conditions such as asthma. Patients these days often have several allergic disorders.

One third of Britons - some 18 million people - will develop an allergy at some time in their lives. And certain severe ones are becoming more common. Peanut allergy alone affects one in 70 children. The number of people being admitted to hospital with allergies has shot up over the last decade, with some types increasing sevenfold.

Why allergies should be on the increase is not clear. For relatively affluent countries like Britain, the very lifestyles that protect us from environmental challenges - everything from vacuum cleaners to double glazing - may mean we are not so well-equipped to respond to the new things we encounter.

In all cases, an abnormal immune response is at the root of the problem. The best advice for sufferers is to avoid the substances that cause the reaction. Failing that, there are medicines that block or relieve the symptoms. However, some people find that the available remedies are not totally satisfactory. The challenges are to understand why this might be, why some people have such severe allergies, and to develop long-lasting treatments or even cures.

Sneezing, runny noses and itchy eyes - it's summer again

Hay fever, over-the-counter remedies can relieve the symptoms - sneezing, blocked nose and itchy eyes.

Although we often think of hay fever as a summer problem, it can actually start as early as January, when the first trees bloom. While late winter and early spring sneezing suggest the sufferer is allergic to tree pollen, summer symptoms are more likely to be due to a grass or weed pollen allergy. Yet other people suffer in the autumn, when moulds flourish. And then there are those who are allergic to pet dander and house dust mite - for these people their "hay fever" can be triggered at any time of the year. Consequently, this form of hay fever is usually called perennial allergic rhinitis.

Every day is different for hay fever sufferers. Sunny, warm and breezy days spread pollen and will generally lead to a worsening of symptoms. Thunderstorms cause pollen grains to burst, leading to a sharp increase in airborne pollen. By contrast, allergy symptoms are generally milder on cloudy and still days. To get an idea of how weather conditions might affect allergy sufferers, the BBC now includes pollen predictions in its weather forecasts.

Pollen is not the only cause of allergic responses. Insect bites can also be problematic for some individuals. Estimates for how many people are allergic to insect stings are hard to come by and vary from between 0.3 and 3% of the population. For most people, an allergy to insect stings will just involve an itchy lump at the site of the bite. But for some people, insect bites can be life-threatening. In a severe allergic or anaphylactic reaction, people can develop difficulty in breathing, swelling of throat tissues, dizziness, even cardiac arrest within minutes of being stung.

Travelling with allergies

Hay fever sufferers can generally predict when in the year their allergies are likely to flare up. But it is easy to get caught out when travelling to foreign countries. Even worse, in large countries with widely differing environments, such as Australia, specific pollens can be a problem at widely different times of the year.

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