Tag Archives: anaphylactic shock

New test for allergies

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A new test to indicate which people are most at risk from life-threatening allergic reactions has been developed by British scientists.

The procedure measures levels of an enzyme in the blood which is involved in allergic reactions that can cause potentially fatal anaphylactic shock.

Medics hope the test could become the definitive, gold standard test for the diagnosis of severe allergic reactions across the world.

One in three Britons suffers from an allergy and the number of cases is rising by five per cent every year.

It was developed by the University of Southampton’s Dr Andrew Walls working with doctors at Southampton General Hospital to help combat a rise in serious allergic reactions to such things as peanuts.

‘Allergic reactions to drugs are increasingly common and reactions to food such as peanuts, tree nuts and fruit are also a concern, particularly in children and adolescents,’ said Dr Walls, a reader in immunopharmacology.

‘But reliable tests for establishing the risk of a reaction have not been available, leaving patients vulnerable to serious reactions in the future.’

Levels of an enzyme called CPA3 are considerably higher in the blood of people who are prone to life-threatening allergic reactions compared with those who are not.

Allergies

Allergies

The level of enzyme can increase rapidly within minutes of the onset of serious allergic reactions, known as anaphylactic shock, and remain elevated for more than a day afterwards.

Using materials developed over a period of years in his research lab, Dr Walls has created a technique to measure these levels in patients and find out who is most at risk.

He said: ‘The development of this test should help to determine the proportion of people with a specific allergy who may be at risk of a life-threatening reaction.


‘This advance allows clinicians to be able to understand the vulnerability of these patients, and either ensure they avoid the problem trigger, or provide them with an injection device so that they can self-administer a drug to fight the onset of a shock, vastly reducing their chances of continued serious attacks.’

Dr Mich Lajeunesse, a consultant paediatric immunologist and a member of the clinical research team, said the test will drastically alter the way doctors diagnose.

‘Severe allergic reactions are frequently overlooked by doctors who call it severe asthma instead,’ he said.

‘This test will help doctors recognise these reactions and provide patients with better aftercare and prevention of future allergic reactions.’

He added: If it proves to be as useful as the early trials suggest, it is likely to become the gold standard for diagnosis of severe allergic reactions around the world.’

The research was funded by the National Institute for Health Research.

Allergies linked to city life

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Children living in built-up cities are much more likely to have food allergies than those living in the country, according to a new study.

Youngsters who grow up in busy urban areas are more than twice as likely to have a peanut or shellfish intolerance than their rural counterparts, a US study has revealed.

The allergies could be triggered by exposure to pollutants at a young age, experts believe.

Conversely, those living in the country could develop immunities from being exposed to bacteria prevalent in nature.

Almost ten per cent of those born in densely populated areas have a food allergy, in comparison to just six per cent of those born in areas with a low population.

‘We have found for the first time that higher population density corresponds with a greater likelihood of food allergies in children,’ said lead author Ruchi Gupta, assistant professor of pediatrics at Northwestern University Feinberg School of Medicine.

‘This shows that environment has an impact on developing food allergies.

‘Similar trends have been seen for related conditions like asthma. The big question is – what in the environment is triggering them? A better understanding of environmental factors will help us with prevention efforts.’

Allergies

Allergies

The study included 38,465 children aged 18 and under from a range of backgrounds, whose food allergies were mapped by ZIP code.

Nearly 40 per cent of food-allergic children in the study had already experienced a severe, life-threatening reaction to food. Their reactions were equally severe regardless of where they lived, the study found.

Just 1.3 per cent of children from rural communities were allergic to peanuts, while 2.8 per cent had the allergy in urban areas.

Less than one per cent of children from the country had shellfish allergies, while 2.4 per cent from cities were allergic.


Past research has shown an increased prevalence of asthma, eczema, allergic rhinitis and conjunctivitis in urban areas versus rural ones.

‘Dr Gupta’s ongoing research on food allergy prevalence is providing critical information to help us address the growing public health issue of food allergies,’ said Mary Jane Marchisotto, executive director of the Food Allergy Initiative, which helped fund the study.

‘We are committed to finding a cure for food allergies and this study provides additional insight about why certain people have food allergies and others do not.’

Food allergy rates have risen sharply in the last 20 years. Symptoms include itching, a red skin rash, swelling of the face, and in the most serious cases, an anaphylactic shock, which can be life-threatening.

It is estimated that around one child in every 14 children under the age of three has one or more food allergies, according to NHS figures.

They are caused when the immune system mistakenly treats proteins found in food as a threat to the body, when in fact they should be harmless.

An estimated four out of five children with peanut allergies remain allergic to peanuts for the rest of their life.