Peanut Allergy Symptoms : Simpler, More Accurate Diagnosis Tests

A new simpler and less risky way of screening children and adults for peanut allergies has been found by a group of Australian researchers. This new blood test offers a less invasive and more accurate test than existing methods.

The Australian researchers have shown in a study, that a twin-element blood test can be used to test and reliably confirm allergies to peanut instead of putting children through risky Oral Food Challenge (OFC) tests. These challenge tests of reactions to peanuts can be risky, expensive and dangerous due to the risks of severe reactions, like anaphylaxis ( see below). There are long delays for suspected cases to be confirmed. For example in Melbourne, Australia, the waiting list for the oral food challenge test more than 12 months.

Many parents concerned about likely allergies have resorted to going to the carpark of local hospitals and feeding their children peanuts, so they could head straight to the emergency department if they had an adverse reaction. This is an intolerable situation. The new testing processed that involve a simple blood test can be used to screen children for a peanut allergies and offer parents a get peace of mind. Dealing with the risk of peanut allergies in schools is a major problem every school must face.

Early Exposure to Peanuts Stops Allergy Developing

Recent research has confirmed that early exposure of infants to peanuts stops the development of allergies in children with high risk of developing it. Children exposed to peanuts in the first year of life, and during their first five years did not deelop peanut allergies even after not eating peanuts for 12-month months.

The researchers claimed that part of the problem was a "culture of food fear" that became a self-fulfilling prophesy. When susceptible children have foods such as peanuts excluded from their diets, the children fail to develop a tolerance.

Blood Tests for Peanut Allergies

The detection of the peanut-specific antibogy IgE (sIgE) in the blood is often used to confirm a reaction or sensitization to peanuts patients, but this does not reliably predict an allergy. The new test is for Ara h 2 which is the major peanut allergen found in more than 90% of patients with peanut allergy, and offers greatly improve diagnosis.

Children from the population-based HealthNuts study in Australia were given skin prick tests to assess their sensitization to peanut. These children were subsequently given an Oral Food Challenge (OFC) test to peanut to confirm allergy status. A randomly selected group of 200 infants (100 with peanut tolerance and 100 with peanut allergy), had blood samples taken. Whole peanut sIgE and tests of the levels of Ara h 2 sIgE in blood samples were measured using fluorescence enzyme immunoassay.

The study found that the dual test correctly identified 60% of subjects with true peanut allergy compared with only about 25% that were identified using whole peanut sIgE test.

The research study concluded that the twin tests of plasma sIgE and Ara h 2 levels in the blood for peanut allergy could potentially reduce the number of OFC test required by as much as 60%. If the blood contains Arah2, this is adequate to confirm an allergy to peanut and no further OFC testing is required.

The Ara h 2 plasma sIgE test should be considered as a new diagnostic tool for screening children for the allergy and for confirming suspected cases.

This method could reduce the potential over-diagnosis of peanut allergies by concerned parents and cut the number of people referred to specialists for further testing. The test is ideal for screening children who are at high risk of food allergies, like those with eczema and with relatives who have food allergies.

Peanut Allergy Incidence and Management

Peanut is the most prevalent allergy to nuts - affecting about 3 per cent of Australian children under the age of two. Peanut allergy is a severe, and sometimes fatal response that is triggered following exposure to peanuts or peanut products, usually by ingestion.

It is caused by the IgE allergy antibodies developed in the body against peanut proteins. In Western countries, surveys have shown that about 0.5% of children (about 1 child in every 200) develop allergic reactions to peanuts by the age of 5 years.

Overall about 1-2% of the general population (all ages) have a clinical reaction to peanuts. While 3% of all children show a positive response to a simple test such a skin prick, only about one third of these will have major allergic responses to eating peanuts. The incidence of peanut allergies in children differs markedly in various countries. Australia has a relatively high prevalence of peanut allergy, for unknown reasons.

Most of the allergic reactions to peanut are relatively small and may cause hives or inflammation around the mouth or on other parts of the body. Other common reactions are vomiting and abdominal pains that develops soon after eating peanuts or various peanut product.

Some sensitive children can develop wheezing, coughing, difficulty breathing or hoarseness of the voice. In the worst cases people may collapse and lose consciousness can occur. Rarely particularly sensitive people have died from the severe allergic response to peanut products known as Anaphylaxis, which is the most severe form of allergic reaction.

Anaphylaxis is serious and must be treated as a medical emergency, requiring urgent treatment, mostly using adrenalin injections, and urgent follow-up medical attention.

Anaphylaxis is a general allergic reaction to other things such as bee stings, which often involves more than one body system (e.g. skin, gastro-intestinaln respiratory and the cardiovascular system). Such a severe reaction can be triggered within 20 -120 minutes after exposure and can rapidly become life threatening. In some people even tiny quantities of food can trigger a life-threatening reaction.

Parents of children with allergy risks should always be very careful to get detailed information from their doctor about any drug that is prescribed for them.

How do I avoid exposing my child to peanuts?

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© 2012 Dr. John Anderson

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