According to the CDC, 32% of adults and 27% of children in the US have at least one allergy. Nasal allergies account for 4.1 million visits to doctor's offices in the US annually. Though the symptoms are most commonly not acutely life-threatening, the total effect of allergies significantly impacts the quality of life and wellness.
It is key to consider the interactions of allergies with other health conditions, as both cause and effect, to begin to understand what substances or foods are triggering reactions. Allergies can and do change with time in many cases, so tracking reactivity helps to avoid restricting food or environmental exposures more than necessary.
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What is Allergy Testing?
Allergy testing can happen in a few different ways, all of which have positive and negative aspects. Regardless of the specific method used, allergy testing will be most helpful in the context of awareness around patterns of exposure and symptoms. This is the first step in considering allergies and is crucial to the process. At this stage, it is important to consider what kind of immune hyperreactivity is most likely.
Is the concern for classic IgE-mediated allergies that cause symptoms such as watery eyes and anaphylaxis due to the rapid release of histamine and other compounds? Is it an inflammatory reaction that seems to be showing a clear association with a particular exposure but maybe doesn't have these classical allergy features? Or, it could be both. But these involve testing in different ways.
In testing for classic allergy, skin reactivity can be measured to small amounts of various allergens that are carefully applied to tiny prick holes made in the skin. The result is based on the visual reaction of redness and swelling at each site. This method benefits from a high level of accuracy in detecting IgE to a specific allergen. However, it is time-consuming, uncomfortable, and not an option for all patients.
Allergy blood tests look for levels of antibodies to different allergens in the blood. Antibodies are made by certain immune cells (B cells) to coat foreign invaders so they cannot enter cells and to identify them to other immune cells, which can then destroy them. There are specific kinds of antibodies that serve slightly different functions.
IgE Antibodies
When allergies and antibodies are discussed, typically, it's a discussion about IgE antibodies. There are two ways in which IgE antibodies are tested in the blood. The first is looking only at total IgE, which is part of a complete blood count with differential (CBC w/ diff), a very common and low-cost test. This is less specific, but in certain cases, it can show when there is a strong allergic reactivity happening. IgE antibodies to specific substances (foods, pollens, etc.) can also be tested, either individually or in a panel that includes many substances in one test. The most common IgE food allergies are peanuts, milk, shellfish, wheat, eggs, tree nuts, soybeans, and fish. It is possible to have IgE antibodies in the blood but not have symptoms of allergy when exposed, so this is a weakness of broad-spectrum testing of IgE without reason to suspect specific substances.
IgG Antibodies
IgG antibodies are another kind of antibody associated with a different mechanism of allergic reactions and food sensitivities. IgG reactions are often delayed, so it is not immediately as obvious what was the cause of symptoms.
IgA Antibodies
IgA antibodies are the most abundant kind of antibodies. They are present on mucous membranes. These are sometimes tested by Functional Medicine providers when food allergy and leaky gut are suspected in combination, especially with Celiac Disease.
Patients Who Could Benefit from Allergy Testing
Allergies can manifest in a variety of symptoms, not all of which we may immediately associate with allergies. Some symptoms that might suggest someone could benefit from allergy testing, either IgE or IgG based, include:
- Anaphylaxis, if the trigger is unclear (testing for IgE antibodies specifically)
- Asthma
- Shortness of breath
- Swelling
- Burning, watery eyes
- Skin rashes
- Eczema (~40% of children with moderate to severe cases have at least one IgE-mediated food allergy)
- Chronic headaches, including migraines
- Abdominal pain
- Bloating
- Diarrhea
- Constipation
- IBS
- Migraine
- Depression
- Chronic fatigue
- Feeling worse in certain environments or after eating certain foods
Benefits to At Home Allergy Testing
Allergy testing can help determine what environmental or food triggers may contribute to symptoms or chronic illnesses. In the case of foods, an allergy test can provide a starting point for an elimination diet to see how these foods may affect symptoms in real life. Environmental allergens can also be tested through a small amount of blood easily collected at home. As a bonus, it is not strictly necessary to go to a doctor's office or lab to have blood drawn or multiple injections to watch for reactions to get more clarity about one's allergies. Just a few drops of blood collected at home and then sent to the lab is all that is needed for many modern tests. This saves time, expense, and discomfort. It reduces the potential for infection exposure in medically vulnerable individuals and significantly reduces the stress of testing for children.
Top Five Functional Medicine Labs Available At Home to Test for Allergies
While there are many allergy testing options, below are the top five commonly used allergen and sensitivity tests functional medicine practitioners use:
P88-DIY Dietary Antigen Test by Precision Point
This test, which uses a novel finger prick device to collect the sample, may be especially ideal for children as it does not require a blood draw and is touted as pain-free. It evaluates for IgE food allergies that may not yet have been identified for a child. The test looks for IgE, IgG, IgG4 antibodies, and complement (CD3) reactions to 88 foods. This broad coverage in antibody types may pick up sensitivities missed by only looking at one marker.
IgE Allergy Explorer & IgG Food Explorer Combo by Diagnostic Solutions
For situations where there may be fewer contextual clues as to where to look for allergens and symptoms suggest some classic allergies, this test covers IgE (classic allergy) antibodies to 150 food and environmental allergens as well as IgG to over 250 foods.
48 Inhalant Panel: IgA/IgG by US BioTek
Usually, testing at a conventional medical office will only be for IgE. If there is reason to suspect that an environmental allergen may be causing a reaction, it is common to also test for IgA and IgG antibodies to environmental allergens. This test assesses commonly inhaled allergens via a simple finger prick.
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Summary
Allergies are an extremely common medical concern across all ages. They also interact with one's health as both cause and effect in the cycle of causation. Identifying the specific triggers for immune hyperactivation is useful in managing related symptoms and potentially employing therapies such as desensitization. In some cases, testing done at home may provide information as reliable and useful as in-clinic testing.
In other cases, home testing may provide additional information about non-IgE immune responses to allergens. Completing allergy testing at home saves time, office visits, and stress, especially for children. In many cases, the most helpful testing can be completed from home. In other cases, in-clinic elements may be useful as well. Making this decision is best with the insights of a medical provider trained in root cause medicine.
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