A reliable 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.
The test is attracting interest from around the world and has been used extensively in clinical research studies with patients in Southampton, as well as in complex cases from around the UK.
Common Allergenic Foods
If a person has an allergy to shellfish, the first time the body comes into contact with shellfish proteins, the body may create a type of antibiotic to neutralise it. However, the next time it will recognise it as a problem again and the immune system will take more aggressive action against it. Shellfish allergies are most commonly caused by crustaceans such as shrimp, lobster, crab, and crayfish. But people have also been known to have a shellfish allergy related to bivalves such as oysters, clams, and mussels, as well as snails, squid, and octopus.
Strawberries can trigger an allergic skin reaction and cause urticaria (hives), pruritis (itching) and contact dermatitis. It's believed those allergic to strawberries may also be allergic to birch pollen. If you have birch pollen allergies, it is common for you to develop secondary food allergies to strawberries or other foods.
Milk allergies are caused by the immune system 'attacking' the proteins in cow's milk as if they were harmful bacteria. Reactions vary from swollen lips and eyes, to diarrhoea and vomiting.
A tomato allergy causes a histamine reaction to raw, cooked or juiced tomatoes, to a substance already present in the skin. People who have a tomato allergy may find they have allergies to other member of the 'deadly nightshade' family, like eggplant, potato and tobacco.
The immune system mistakenly identifies certain egg proteins as harmful. When the body comes in contact with egg proteins, immune system cells (antibodies) recognise them and signal the immune system to release histamine that cause allergic signs and symptoms. Both egg yolks and egg whites contain proteins that can cause allergies, but allergy to egg whites is most common.
People with a wheat allergy have an abnormal immune system response to at least one of the proteins that exist in wheat. The allergic reaction involves IgE (immunoglobulin) antibodies to at least one of the following proteins found in wheat - Albumin, Globulin, Gliadin and Glutenin (gluten). Those with wheat allergies have symptoms of breathing difficulties, nausea, hives, bloated stomach and an inability to focus.
Peanuts have a high level of the allergen chemical and in those with an allergy, they clash with the immune system, causing a huge surge of histamine in the body. This causes the blood vessels to leak fluid which causes the swelling reaction. Sometimes, peanut allergies can trigger severe reactions, like anaphylaxis, which causes dangerous breathing problems.
Yeast exists all over our body and in our digestive tract which is also known as candida. It is believed that in some people the overgrowth of that yeast triggers the immune system to react and produce yeast allergy. Common symptoms of yeast allergy include skin rashes, eczema, headaches, fatigue, lack of concentration and sometimes change food pattern.
Hot and spicy foods like black pepper, cayenne pepper, chili powder or jalapenos can cause acid reflux and gastritis which can trigger food allergy symptoms in some people.
Like in cow's milk, protein in the sesame seeds can trigger allergic reactions in those prone to an allergy. This doesn't exclude sesame seed oil, as its believed that just 3ml of sesame seed oil can result in allergic reactions.
Medics hope it could become the gold standard test for the diagnosis of severe allergic reactions across the world.
"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. 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.
Foods That Fight Allergies
The anthocyanin compound, found in purplish-red coloured food like beetroots, berries, red grapes and cherries, is a powerful anti-inflammatory agent which help fight allergies.
Turmeric, the yellow-coloured spice commonly found in hot curries, is a great way to ward off pesky allergies. Previous research discovered turmeric has super strength antioxidant qualities which work just as well as anti-inflammatory-rich foods when fighting allergy attacks on the body.
Lemons contain high levels of hesperetin, a potent phytonutrient which packs a powerful antioxidant punch when it comes to beating allergies. It's also a great anti-inflammatory, anti-carcinogenic and even lowers cholesterol as an added health boost. These are especially useful for hay fever because of its antihistamine qualities.
Quercetin is an antioxidant, anti-inflammatory and anti-histamine which helps ward off allergy symptoms like histamine-induced sinus congestion and runny eyes and noses - all common with hay fever. This is because quercetin is believed to help lung function and reduces the risk of lung infection. Add onions to every meal, along with other quercetin-rich foods like apples, parsley, citrus fruits and black tea.
Mango: Vitamin C
Vitamin C is a great way to keep your immune system in greet shape so that allures have less chance of ruining good health. Mango's are a great alternative if you find oranges too bitter.
These, along with quercetin, are great for providing the body with natural antihistamine which helps prevent the release of histamine which causes allergies to attack. They also boast impressive anti-inflammatory compounds. Garlic is a great way to boost your flavonoid intake as well as <a href="http://www.huffingtonpost.co.uk/2012/01/19/flavonoid-rich-foods-reduce-heart-disease-diabetes_n_1216378.html" target="_hplink">these flavonoid-rich foods</a>.
Omega-3 Fatty Acids are thought to reduce allergic reactions through their anti-inflammatory properties. Omega-3 Fatty Acids are found in such foods as cold-water fish (think salmon), and walnuts.
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. This could radically change the way clinicians manage those affected.
Dr Walls 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 this test 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 (NIHR).