New test is close to 100 per cent accurate at spotting nut allergies

New safer blood test is close to 100 per cent accurate at spotting nut allergies

A new blood test promises to diagnose food allergies more accurately and offer a safer alternative to current testing practices.

A trial by doctors at Guy’s and St Thomas’ Hospital in London has found that the test — called the basophil activation test (BAT) — is close to 100 per cent accurate at spotting nut allergies.

Allergic reactions occur when the immune system overreacts to a trigger —usually food, medication or an environmental irritant — causing the release of histamines, substances that try to rid the body of the allergen. This leads to symptoms such as itchy rashes and swelling.

A trial by doctors at Guy’s and St Thomas’ Hospital in London has found that the test — called the basophil activation test (BAT) — is close to 100 per cent accurate at spotting nut allergies

The most severe form of allergic reaction, anaphylaxis, can lead to life-threatening symptoms such as breathing difficulties and loss of consciousness.

Diagnosing allergies usually involves skin prick tests, where a drop of liquid containing a substance the patient may be allergic to is placed on their forearm. The skin is then scratched, so the liquid seeps into it.

Blood tests, which check for IgE, an antibody produced when there is an allergic reaction, can also be used.

But both of these tests are far from perfect and can lead to a high rate of false positive results, meaning an allergy is indicated when there isn’t one.

In skin prick tests, for instance, that’s because the amount of the food protein on the arm is often larger than the amount you would absorb from digestion (which may not cause a problem).

Because these are inaccurate, to confirm the diagnosis, allergy patients may be given an oral food challenge (OFC), in which the patient eats a food they may be allergic to in tiny amounts, while they are under supervised hospital conditions. This can be risky as it may provoke anaphylaxis.

It’s hoped that the basophil activation test will offer a safer option to OFCs. It involves mixing a small amount of the food the patient is thought to be allergic to — for example, peanut protein — with a sample of their blood.

Diagnosing allergies usually involves skin prick tests, where a drop of liquid containing a substance the patient may be allergic to is placed on their forearm. The skin is then scratched, so the liquid seeps into it

The sample is then analysed to check the basophils — a type of white blood cell involved in food allergies. In particular, the test detects the presence of a molecule called CD63 on the basophils’ surface, which is a sign that the patient is allergic to that particular type of food.

Results are available in three hours. The test is 96 to 100 per cent accurate at diagnosing nut and sesame seed allergies, a study of 92 children by Guy’s and St Thomas’ Hospital found.

It also reduced the number of OFCs needed, the Journal of Allergy and Clinical Immunology reported recently. The researchers suggest the technique could be used routinely within years.

Graham Roberts, a consultant in paediatric allergy and respiratory medicine at University Hospital Southampton NHS Trust, said: ‘This is exciting as a lot of the time skin prick testing and IgE tests are inconclusive. BAT gives you more (and different) information, which is actually complementary.

‘However, you need blood that has just been taken from the patient, and it needs to be run within a few hours of the blood being taken, so hospitals will need the right set-up to do this.

‘But it will save children from doing challenges which can put the patient at risk.’

Could increasing babies’ intake of vitamin D prevent allergies? Scientists at Murdoch Children’s Research Institute in Australia are hoping to find out.

Researchers are giving 400IU of vitamin D daily to more than 3,500 infants aged six to 12 months. When they turn one they will be tested for allergies and checked for allergic symptoms such as eczema. Vitamin D is thought to be vital to the development of the immune system.

App that can help reduce risk of falls in older people

An app-based exercise programme has been developed in a bid to reduce falls in older people.

In a trial run by researchers in Australia, more than 500 adults aged 70 and over were given a tablet computer with information about balance exercises, as well as a foam cushion, stepping box and exercise mat.

They were asked to exercise for two hours a week for two years, with the level of the challenges increasing.

The results were compared with a group who had only received a tablet containing details about diet, exercise and fall risk factors.

The programme, called Standing Tall, was found to significantly reduce the rate of falls after two years, according to the study published in The BMJ. 

Jab may offer longer-lasting arthritis relief

Injections of a new drug could offer long-lasting pain relief for arthritis.

The remedy, which targets the knee joint, contains a steroid called fluticasone, which is wrapped in a dissolvable coating that naturally degenerates in the body over time.

Although knee arthritis is commonly treated with steroid injections, the new coating extends the release of the drug and therefore the period of pain relief.

Results show this can last for up to six months (compared to up to two months with existing injections).

Around 200 patients with knee arthritis are now taking part in a 42-week trial run by Eupraxia Pharmaceuticals in Canada.

They will be monitored after a single 15mg injection of either the drug or a placebo.

Could eating wrinkly peas ward off type 2 diabetes?

A ‘super pea’ might hold the key to reducing the risk of type 2 diabetes.

The dried mature pea is naturally packed with resistant starch, which takes longer to break down in the body.

This helps prevent sugar spikes, according to new research from Imperial College London. The study, published in the journal Nature Food, showed wrinkled peas were more effective than smooth-skinned peas.

The same effect was seen in people who consumed a flour made from the pea. Researchers suggested eating the pea in either form could reduce the risk of type 2 diabetes.

Listening to music lowers blood pressure and heart rate, according to a study from Hiroshima University Hospital in Japan.

This found that people at risk of high blood pressure who listened to relaxing piano and flute music for 30 minutes a day, five days a week, for a month, had a significant drop in heart rate. Higher blood pressure is associated with cardiovascular damage.

The music therapy is thought to increase levels of dopamine and slow down brain activity, leading to changes in mood, anxiety and stress levels.

Writing in the Journal of Clinical Hypertension, the researchers said this might be an option for preventing high blood pressure.

Listening to music lowers blood pressure and heart rate, according to a study from Hiroshima University Hospital in Japan

Paws for thought

The health problems we may pass to our pets. This week: Flu

Humans may be able to pass on a strain of the flu virus to their pets — or that was the suggestion after two cats died of pneumonia following their owner’s swine flu (or H1N1) in 2009.

Follow-up research by Oregon State University and Iowa State University in the U.S. also found 11 other cats, and one dog, infected with swine flu.

But Professor James Wood, a specialist in zoonotic diseases at Cambridge University, told Good Health that flu generally doesn’t pass between humans, cats and dogs.

‘One expects to see occasional infection “spillover” between species, but these are never replicated in the population as a whole — so it’s important not to over-interpret this study,’ he explains.

However, flu does pass from humans to ferrets, he says — so avoid handling them while you’re sick.

Try this

Nairn’s Gluten Free Oats Your Way is made from wholegrain oats and dried fruit pieces. It is suitable for those with coeliac disease and is high in fibre, with 4.3g (or just under a sixth of your daily needs) in each serving. — £2.71 for 375g, shop.nairns-oatcakes.com

Mask medicine

Ailments caused by wearing a mask and how to treat them. This week: Rosacea

Rosacea is a common skin condition that leads to redness and spots across the nose and cheeks.

The exact cause isn’t known. but as Dr Mark Hudson-Peacock, a consultant dermatologist at Stratum Dermatology Clinics in Canterbury, explains, ‘skin is aggravated by heat and stress, so a mask can make the condition worse. The friction of the material can also irritate the skin.’

What to do: Wash your face with a gentle cleanser for sensitive skin and use non–irritating moisturiser, says Dr Hudson-Peacock.

‘Also avoid perfumed oil containing skin products which may aggravate rosacea.’

He suggests choosing masks in breathable fabrics (such as cotton) and those with an antibacterial coating, too.

As Dr Mark Hudson-Peacock, a consultant dermatologist at Stratum Dermatology Clinics in Canterbury, explains, ‘skin is aggravated by heat and stress, so a mask can make the condition worse. The friction of the material can also irritate the skin’ 

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