"Two roads diverged in a wood, and I took the one less traveled by, and that has made all the difference" Robert Frost

Allergy and Intolerance Testing

Updated: May 11, 2019

Food. Oh how we love to eat it, after all - it nourishes and heals us. Sadly, growing numbers of people, often young children, are showing various signs and symptoms of certain foods not really loving them back.

While there isn't a magic solution that makes finding out exactly what foods or other potential allergens we may be reacting to, the journey to resolving allergies and intolerances certainly starts with having a better understanding of what we're dealing with. One question asked a fair amount in my wellness community is how do they navigate through the testing and food elimination process, and how meaningful are the results?

While I am not a doctor or naturopath, I've studied the topic in some depth and here is my basic overview. Because of the complexity of immunity, I encourage everyone to do a variety of reading and research as well.

What are Allergies, Intolerances and Sensitivities?


Our immune system is programmed to fight infection to maintain a healthy internal environment. Its role is to protect us daily from foreign agents and pathogens and so it acts when it discovers an intruder - and that response can be vigorous. When a pathogen can't be cleared, our innate (non-specific) immune systems are switched to an adaptive (specific) process which occurs at a cellular level, with multiple biochemical processes in place that identifies and attempts to eliminate pathogens from the body.

Lymphocytes are created in the bone marrow, which secrete proteins (antibodies) that bind to foreign molecules (antigens) and marks them for clearance/destruction.

An antigen is any substance that causes your immune system to produce antibodies, typically proteins, and an allergen is any antigen that causes an allergic reaction. The interaction between an antibody with an antigen is the basis for the allergic response, and as little as one single molecule could be needed to trigger it. There are five different types of antibodies produced by our immune system: Immunoglobulin A (IgA), IgG, IgD, IgM, IgE.

Given that the term allergy is often bandied about, it's important to note a "true" allergy (mediated by an IgE response) is when after coming into contact with an antigen, the immune system which has previously identified it as a foreign invader creates IgE antibodies (think of these like the soldiers of the immune system) against it, which bind to the antigen and then a histamine release is triggered by mast cells. This is a highly inflammatory process and symptoms range from person to person, from quite mild through to potentially life threatening. Histamine acts as a messenger, traveling to the site of irritation to activate a particular response (i.e. inflammation or mucous production) to try and expel it from the body. The allergic reaction generally depends on the amount of histamine released ,and reactions can be immediate or delayed. Symptoms of a IgE mediated allergy often involve those places where mast cells are most abundant which are the surface of the skin, nose, eyes, lungs and the GI tract hence why symptoms such as hives, welts, scratching, sneezing, wheezing, eczema, coughing and digestive distress are typical, with the most serious being anaphylaxis (a rare severe reaction that has catastrophic consequences if adrenaline is not injected into the bloodstream fast enough). What we see as allergic 'reactions' could also be described as attempts by the body to clear the antigen as fast as possible using the nose, sinus, lungs/airways, eyes, ears, skin and/or the gastrointestinal tract. This is how I see eczema and why I don't tend to describe it a skin condition nor a steroid cream deficiency, but rather an attempt by the body to clear the inflammation via the skin - which is rather different. There are three types of allergies: food, chemical and environmental but why does our immune system suddenly decide certain proteins are problems and allow allergies to occur? Well, that's a topic for a whole other article, but we do know allergies require at least one exposure for antibody development to occur. This process is known as sensitisation and can happen at any time and at any age, but in my experience certain factors may influence this.

Generally when I see the types of symptoms outlined, I usually suggest allergy testing as at least a place to start because in removing known allergens, we also tend to reduce the inflammatory response, and this should support the gut healing process to occur in a more efficient manner.

Click here to view a handy chart that helps determine allergic reactions in children!


An intolerance can sometimes look quite similar to an allergy but with two key differences - IgE antibodies are not created and anaphylaxis is not a risk. While intolerances are considered far less serious, they are likely also far more common with symptoms often looking like (but not exclusive to): bloating, diarrhea, abdominal pain or headaches.

IgG Food Intolerance

Sometimes one of the other antibodies may be produced - IgG. These are more aligned to white blood cells, and reactions are typically delayed (up to four days) rather than immediate, however there is still a corresponding inflammatory response.

Because only IgE antibodies are considered relevant for allergy diagnosis, testing for IgG must be privately funded (and is expensive, prohibitively so for many). It can be useful in helping determine elimination diets for chronic conditions related to inflammation such as autoimmunity when a delayed reaction can be observed yet the RAST is negative.

Digestive Intolerances (i.e. Fructose, Lactose or Gluten etc)

This is where there is an absence of a compound needed to fully digest a food, and could even look like the mysterious "Irritable Bowel Syndrome"

For example after weaning, at some point our body ceases to produce the digestive enzyme lactase which means it can no longer break down the milk sugar lactose, which then causes digestive distress, hence = lactose intolerance. Note: raw milk still contains the live enzymes needed for digestion, but pasteurised milk does not, however if you are allergic to milk, your immune system will be triggered by the presence of the protein. To make 'lactose free' milk, the producers merely add back in the digestive enzyme. These may be identified during food and symptom tracking or an elimination diet, however there are some other tests that may help. or there are some other tests you could discuss with your preferred health practitioner.

Coeliac Disease

While this involves the immune system and antibodies are created, it also does not come with the risk of anaphylaxis. Triggered by eating gluten, a protein in wheat and other grains, gastrointestinal reactions are common but other more serious health issues may occur if left unmanaged so this does require strict avoidance of gluten at all times.

You'll need to ingest gluten twice a day for at least four weeks if you wish to pursue formal testing.


This basically covers everything else - where there is an adverse pattern of response after exposure, but can't be defined by any of the above. It may be cumulative or instant but the immune system is not intimately involved.

You could be 'sensitive' to specific food additives or compounds such as MSG, sulphites, salicylates, amines etc. You may see fatigue, behavioural changes such as hyperactivity or aggression, digestive distress or something else. However, something that probably needs to be raised here is that there is often some type of consequence to consistently poor, or politely 'less than optimal' food choices. Basically if we eat food that is hard to digest or contains certain things that may trigger an inflammatory response, our bodies will probably try to tell us in some way, hence the importance of learning to check into our bodies and seeing if they're trying to tell us something!

So in a nutshell...

  • An allergy causes the immune system to create IgE antibodies which has a trickle down response as it attempts to remove the allergen from the body.

  • An intolerance response can look similar to an allergy in many ways but no IgE antibody is produced. The reaction is typically delayed or perhaps it's just that your body can't process the food efficiently or at all.

  • A sensitivity isn't as well defined but when you come across it, not so great things may happen to you.

  • Crappy junk foods will likely make you feel crappy.


Allergy Diagnostic Testing

If you think you might be dealing with an allergy, you'll first need to see your doctor or an immunologist. They will take a history, do a physical check and can order either or both of the below tests however this reads a lot more straightforward than it may be in reality. My daughter presented with eczema from around three months onwards, and at 5 months, the first GP we saw regarding this was resistant and told us that eczema and food allergies were not related and told us just to use stronger steroid creams (we later found out this is typical). I trusted my instincts and sought a second opinion from a more open-minded doctor. My daughter's tests can back with five allergens: from moderate to extremely high. Allergies are diagnosed via two methods. It's important to note that all tests have significant rates of false results, but I do still recommend formal testing especially when someone presents with certain symptoms. There needs to be at least one prior exposure for the immune system becomes sensitised, whether we are aware of that exposure or not.

RAST (radioallergosorbent) blood test:

Blood is drawn in the usual way, and a lab measures the production of IgE antibodies in response to the allergens requested on the form. False positives and negatives are somewhat common but generally, the higher the level, the more likely an allergic reaction however no test can fully accurately forecast the potential severity of the next reaction.

Skin Prick Test (SPT) method:

Typically used for identifying classical/immediate allergy reactions and cheaper for labs to run, this measures the size of any welt our skin produces when exposed to a tiny amount of the allergen.

Compared to a control which is always included, the welt gives a rough indication to how severe an actual reaction *could* be. Considered unreliable for infants under 12mo of age, you will have to ensure no antihistamines or steroid creams are used within 24 hours of the test. Sometimes you can order both tests especially working with an allergy specialist or immunologist to find the test results match or differ, so in my opinion they do test for slightly different things and I tend to reserve suggesting them both but rather matched on the client history I'm working with. We also have to consider test results alongside tracked symptoms, knowing the results aren't necessarily fixed, but rather a snapshot at that particular time.

Non Diagnostic Testing for Intolerances and Sensitivities

These don't and cannot not test for true allergies, but rather help to determine intolerances or potential sensitivities. These methods aren't validated or approved by the conventional model, and may be expensive and irrelevant however I can also see that allergy testing is very limited in its application even if your GP will agree to it, and so when an individual is not able to address their symptoms, such tests may help shine a light on identifying triggers.

IgG Intolerance Test

Some labs have also added Candida to the IgG Food Allergy Test given this yeast imbalance can cause significant gut issues. If you'd like to order the IgG food panel which includes testing for 96 foods including common dairy products, fish/crustacea/mollusk, vegetables, grains/legumes, nuts, fruits and meat, contact me via email. This is a blood spot test which is collectable at home. The cost is NZ$430 including GST for the test and a 20 minute followup.

Hair Strand Analysis

This is when strands of hair is examined under a machine that measures energy patterns to identify potential triggers and it also claims to be able to make other health insights. It's non invasive and thus there is far little trauma for little ones involved. Costs vary from as little as $25 to over $100 and feedback is mixed, but I do see it as potentially helpful and many others would agree. Like all tests, we need to interpret the results alongside observations before taking action but for those seeking a more simple, straightforward option they've often been really glad to have this done. I don't personally recommend it.

Applied Kinesiology/Muscle Testing

I am fascinated by this modality however I've also seen that it can be misused. It relies on the principle that the body never lies. Kinesiology is the study of movement but Applied Kinesiology was created later by a chiropractor. Basically the person is asked to hold a specific item (or a vial containing the energetic imprint of an item) - a parent holding the child can become the surrogate - and pressure is put on a limb to test how the body responds. If the limb holds firm when gently pressed, that item is considered okay but if it cannot easily stay firm against the slight pressure, then the body is seen to be weakened by exposure to that item and it's deemed a trigger.


Often considered the gold standard in identifying triggers, it is not a diagnostic tool and it can take a while to establish patterns especially in breastfed infants. As the title says, you eliminate a food/several foods usually until symptoms disappear, and then provoke (challenge) the body by reintroducing one by one and monitoring. Not recommended for known or suspected severe allergies unless you are doing a formal food challenge with the express knowledge and direct supervision of your doctor or immunologist. If you can reintroduce without problems, then it's considered acceptable to include into your diet. If you react in any way, it's likely you're sensitive and may need to eliminate again while you continue your efforts. The biggest issue I see here is usually our own desire for the results to be positive. Often I'm asked "could that reaction been a coincidence?". My answer is generally, possibly... but probably not. Instead of the word reaction, I like the word response. Trust your observations for what they are, and if you're not sure, go through the process again.

The reason testing is so important, is that an immune system or body dealing with constantly responding to a food that is triggering a response is not able to do the rest of its jobs so efficiently - meaning many who are still being exposed to their allergens or triggers are often in poorer health without realising because of the chronic inflammation. Funnily enough, it's also often the foods we crave the most that are the foods we struggle with the most too! The best way to prevent symptoms and reactions is investigate via testing or observation, developing awareness and avoidance/elimination. I really do encourage we all learn to LISTEN to our bodies. All the best for your allergy and intolerance testing journey.




That makes me happy. I love to write - it's a creative outlet of expression for me which brings me much enjoyment, even when talking about serious topics. If something has resonated with you and you'd like to explore further please get in touch, or if you'd like to shout a coffee to say thanks, I'll be incredibly grateful for the support. Either way, I'm grateful you've read my work.

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integrative nutrition

holistic eczema expert

Maryana was introduced to the principles of holistic family wellness when her daughter was diagnosed with eczema and food allergies as an infant. She dedicated herself to deep diving how to resolve these naturally and now helps other families to implement a strong nutrition and lifestyle foundation to build beautiful skin and balanced immunity from the inside out. She lives in New Zealand with her integrative wellness practitioner husband, their daughter and three rescue animals.

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Maryana Lishman is an Integrative Nutrition and Holistic Eczema Coach who is passionate about supporting and empowering families to reach their health goals. All information, opinions, and recipes provided on this website are not intended to diagnose, treat, cure or prevent any disease or condition and are not a substitute for advice from  your doctor.  are her own and should not be taken as prescriptive or medical advice. Please seek professional advice before making changes to your diet or lifestyle.  Throughout this site, there are various affiliate links I may earn a small commission from, at no extra cost to you, should you decide to purchase.

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