If you have an unsettled baby and you suspect there they might have an allergy, it is important  to be well informed about which ones are scientifically proven to diagnose and allergy in your baby and which ones are likely to waste your money. Read on to find out more.

Allergies can be very difficult to diagnose in babies because their immune systems have not yet developed enough to give accurate results. However allergy testing for babies  can be used as a diagnostic tool for determining what an infant is allergic to, this is used along side a detailed allergy history and determining the symptoms.

What is Allergy?

 Allergy is a condition that occurs when the immune system reacts to a foreign substance known as an allergen(such as pollen, dust, or food) and launches a defence response against them causing an allergic reaction. In some cases, the immune system identifies the substance as harmful and triggers a response that can cause a range of symptoms, from mild to life-threatening. These symptoms vary from mild to severe, including itching, hives, runny nose, watery eyes, swelling, eczema and even anaphylaxis in severe cases. Allergies can develop at any point in life, including infancy. 

Allergies can be triggered by different substances, including: - Foods – such as milk, eggs, peanuts, tree nuts, soy, wheat, fish, and shellfish - Insect stings – such as bees, wasps, and fire ants - Medicines – such as antibiotics, aspirin, and NSAIDs - Pollen – from trees, grasses, and weeds - Animal dander – such as from cats, dogs, and horses - Latex – found in some gloves and balloons. It’s important to note that not all people react to these substances. However, those who develop allergies may experience severe reactions, making it hard for them to perform daily activities.

There are different types of allergic responses called IgE allery and Non IgE allergy.

Difference between IgE and non-IgE allergy in babies

Allergic reactions can be categorized into two types, IgE and non-IgE allergies. While both types of allergies can affect babies, they differ in the way they occur, the substances that trigger them, and the symptoms they cause.

IgE Allergies

IgE allergies, also known as immediate-onset allergies, occur when when the immune system produces an excessive amount of antibodies called immunoglobulin E (IgE) in response to allergens. This process triggers an immune reaction that releases histamine and other substances.  Some common substances that can trigger IgE allergies include cow's milk, peanuts, nuts, shellfish, pollen, and pet dander. In babies, the symptoms of IgE allergies can range from mild to severe and occur within minutes to up to 2 hours after exposure to the allergen. Symptoms include:

1. Hives or skin rash

2. Swelling of the face, lips, tongue, or around the eyes

3. Runny or stuffy nose

4. Coughing or wheezing

5. Trouble breathing

6. Stomach cramps, diarrhoea, nausea, or vomiting

Non-IgE Allergy:

Non-IgE allergy, on the other hand, does not involve the IgE antibody but rather other antibodies and components of the immune system apart from IgE antibodies, the allergic response tends to be more localised to the area of contact, eg the gut where inflammation can occur. As a result the reactions do not appear immediately after ingestion of the food and symptoms usually relate to reactions in the gastrointestinal tract such as vomiting, bloating and diarrhoea. This type of allergy is also known as delayed-type hypersensitivity or cell-mediated hypersensitivity. Because there is not an immunoglobulin E response this type of allergy cannot be diagnosed by a blood test or any diagnostic tests. 

Unlike IgE allergy, the symptoms of non-IgE allergy take longer to develop, typically one to three days after exposure to the allergen. The symptoms of non-IgE allergy can include:

1. Eczema or skin rash

2. Diarrhoea or vomiting

3. Stomach cramps, bloating and gas.

4. Irritability or lethargy

5. Runny or stuffy nose

6. Redness or itchiness around the mouth or anus

Non-IgE allergy is commonly associated with food allergies, and the most common allergens include cow's milk, soy, egg and wheat.

Diagnosis of IgE and Non-IgE Allergy.

Diagnostic Tests for Non IgE Mediated Allergy

Non IgE mediated allergies cannot be diagnosed by any diagnostic tests, the process of diagnosis is preformed by an adequately trained professional who specialised in allergies such as a GP, paediatrician or paediatric dietitian. This process involves taking a detailed medical history and assessing the symptoms. To diagnose a non IgE food allergy the allergen must be removed from the child's diet for a period of 2-4 weeks and then reintroduced.  For more information on how to diagnose non IgE mediated cow's milk allergy click here to read this blog.

For a step by step guide to diagnose cow's milk allergy - see my mini course here

Recommended Diagnostic Tests for IgE Mediated Allergies

An allergy test is a medical assessment procedure carried out to determine if a person is allergic to a specific substance. The test measures the amount of specific immunoglobulin E (IgE) antibodies in the blood or skin reaction triggered by allergenic proteins. When an individual has an allergic reaction to a particular allergen, their body produces IgE antibodies that trigger the release of histamine and other chemicals that cause allergic symptoms. The allergy test helps in identifying the specific allergen that triggers the allergic reaction.

1. Skin prick test (SPT):

Skin prick allergy tests are a type of diagnostic test used to determine if a person is allergic to a specific substance. During the test, a small amount of a potential allergen is placed on the skin, usually on the forearm or back, and the skin is then pricked or scratched with a small needle or lancet. If the person is allergic to the substance, the body will produce IgE antibodies and histamine and cause a localized reaction at the site of the prick, such as redness, swelling, or itching. The test is commonly used to diagnose allergies to environmental allergens, such as pollen or animal dander, as well as food allergies. A positive result is indicated by a wheal and flare reaction at the site of injection. This is measured against the 'control'. The control is a prick of histamine. Our bodies will naturally react to histamine so the control wheal flare is measured and the allergy skin prick is measured and compared against each other. If the allergy wheal flare is the same or higher than the histamine control wheal flare then this confirms the likeliness of an allergy to that food or environmental substance. Although these tests are scientifically proven, clinicians are not likely to preform these invasive test on babies and young children under 2 years of age because there is limited research available. However, some studies suggest that SPTs can be accurate in this age group if performed correctly and interpreted carefully.

It is important to note that the interpretation of SPT results in children under 2 may be more challenging, as their immune systems are still developing and their skin may be more sensitive. Additionally, infants and toddlers may have more difficulty sitting still during the test, which can make accurate placement and reading of the test results more difficult.

Overall, the accuracy of SPTs in children under 2 may depend on several factors, including the skill and experience of the practitioner, the specific allergen being tested, and the child's individual immune response. Therefore, the results of SPTs in children under 2 should be interpreted and used cautiously, in conjunction with other clinical information such as the child's medical history and symptoms.

2. Serum IgE test:

The Immunoglobulin E (IgE) RAST test is a blood test that measures the levels of IgE antibodies to specific allergens. This test is moderately accurate; it has a sensitivity of 80-90% and a specificity of 95-100%. This means that the test accurately identifies individuals with allergies 80-90% of the time and correctly identifies those without allergies 95-100% of the time.

The accuracy of the IgE RAST test depends on various factors, including the type of allergen being tested, the patient's medical history, the age of the child being tested, allergic symptoms, and the laboratory performing the test. It is important to interpret the results of this test with caution and in conjunction with other clinical information to make a definitive diagnosis of allergies. Additionally, false-positive and false-negative results can occur in rare cases. Hence, proper interpretation of the test results with the help of a healthcare professional is necessary. Please note that these tests although the best we have are not routinely done in children under the age of 2. Children under the age of 2 years have an immune system that is weak and still developing so results are generally considered to be inaccurate. However in some cases the clinician may preform them give accompany other medical evidence and history to make a firm diagnosis.

3. Oral food challenge:

A supervised test, usually in the hospital environment, where the child is given increasing amounts of the suspected allergen to eat while being monitored for symptoms of an allergic reaction.

4. Patch test:

A small amount of an allergen is placed on a patch that is then attached to the skin. The patch is left on the skin for 48-72 hours and monitored for any reaction. This test not not routinely performed now. 

5. Elimination diet:

Certain foods are eliminated from the child's diet for a period of time and reintroduced one at a time to see if there is a reaction.

6. Nasal provocation test:

A small amount of allergen is placed in the nasal cavity and the child is monitored for any symptoms of an allergic reaction.

It is important to note that these tests should only be performed under the supervision of a qualified healthcare professional and in a controlled environment to ensure the safety of the child.

Non Recommended Allergy Tests

1. IgA allergy testing:

IgA allergy tests are blood tests used to detect allergies to foods or substances that can cause an immune response in the body. Immunoglobulin A (IgA) is an antibody that is found in the mucous membranes of the digestive and respiratory tracts, making it a useful marker for detecting allergies in these areas. The test involves collecting a blood sample and measuring the levels of IgA antibodies against different allergens. This information may be used to identify the substances that a person is allergic to however this is a controversial topic in the field of allergy testing, and its accuracy is still debated by medical professionals. Some studies suggest that IgA testing may lead to false-negative results and miss some allergies, while other studies claim that IgA testing is an effective method for identifying food allergies. Additional research and medical evidence are needed to fully understand the accuracy and limitations of IgA allergy testing. IgA immunoglobins are process readily from the foods we eat, so often they can show high to certain foods, just because we eat these regularly in our diets. This does not mean we allergic to those food. These tests are very unreliable and are not scientifically proven and are therefore not recommended as a suitable test in children with allergies.

2. Bioresonance:

Bioresonance allergy tests are a form of alternative medicine that uses a device to measure the body's electromagnetic signals in response to different allergens. The test involves placing electrodes on the skin and exposing the body to a range of substances, such as foods, pollen, and animal dander. The device then measures the body's response to each substance and determines which ones trigger an allergic reaction. Proponents of bioresonance allergy testing claim that it is a more accurate and non-invasive alternative to traditional allergy testing methods. However, there is little scientific evidence to support its effectiveness, and it is not widely accepted by the medical community.  Several studies have shown that these tests lack scientific validation and carry high risks of false positives and negatives. Therefore, the accuracy of bioresonance allergy tests is questionable and cannot be relied upon for accurate diagnosis and treatment. It is essential to consult with a qualified healthcare provider for proper diagnosis, treatment, and management of allergies.

3. Vega allergy tests:

VEGA allergy testing is a type of electrodermal screening (EDS) used to identify allergies and sensitivities to various substances. During the test, a practitioner applies a small electrical current to the skin while holding an electrode in one hand and a vial of a particular substance in the other hand. The electrical response of the body is then measured and analysed to determine whether there is an allergy or sensitivity to the substance being tested. VEGA testing is considered controversial and not widely accepted by mainstream medicine as a valid form of allergy testing. However, according to the American College of Allergy, Asthma & Immunology (ACAAI), Vega allergy testing, also known as electrodermal testing, is not scientifically proven to be accurate or reliable in diagnosing allergies. The ACAAI states that these tests possess no scientific rationale and produce inconsistent and unproven results. Therefore, they do not recommend these tests as valid means of diagnosing allergies. Instead, they recommend using validated and reliable allergy testing methods, such as skin prick testing and blood tests - see above. 

 Conclusion

The first thing you should do if you suspect that you baby has an allergy is to approach you GP or physician for further advice and possible onward referral to a dietitian or Paediatrician who will be able to assess their symptoms and advice further. Recommended allergy tests are on performed by highly training Paediatricians who specialise in allergies in children and who work as a multidisciplinary team. The blog aims to highlight evidenced based allergy tests and provide you with information so that you make the best decision for your child. For more information on Cow's Milk Allergy click here.