About 50 years ago, the discovery of IgE marked a new era in immunology. This antibody shields you against parasites and cancer, but it also triggers intense allergic reactions. Learn what this lab marker can tell you about your health and how to keep it in check.

What Is IgE?

Immunoglobulin E (IgE) is a type of antibody. Our immune cells called B cells (or plasma cells when activated) produce antibodies in response to allergens, pathogens, cancer cells, and other threats. Antibodies help our immune cells recognize and remove these “intruders” [1, 2].

The primary role of IgE is to protect your body from worm and other parasite infections. It is also involved in allergic reactions [3, 4].

Scientists assume that IgE flags all kinds of unwanted components, acting as the “gatekeeper” of our immune system. In response to these components, T immune cells release the cytokines IL-4 and IL-13, which stimulate the production of IgE antibodies [5, 6].

Allergies

Source: Wright et al., 2015

IgE mediates the most common allergic reaction, known as type 1 hypersensitivity. This is an uncontrolled immune response to components in the environment (antigens) in allergic diseases such as [7]:

  • Asthma
  • Atopic dermatitis (eczema)
  • Allergic rhinitis (hay fever)
  • Food allergies

An allergic person produces specific IgE antibodies to an allergen during the first contact, known as sensitization. These antibodies bind to immune cells (mast cells and basophils), enabling them to recognize the allergen next time [8].

Next time the same allergen reaches the body, massive amounts of IgE stimulate mast cells and basophils to release histamine and other “defense weapons.” This results in unpleasant symptoms ranging from skin itching to life-threatening conditions [9, 10].

Our B cells produce a specific type of IgE for each allergen, and that’s why you can be allergic to only one thing, such as peanuts, or a couple of them [11].

Parasitic Infections

This antibody evolved as our defense mechanism against parasitic infections. The presence of parasites (helminths) in your body triggers vigorous IgE production [6].

The resulting chain reaction also involves mast cells, and it’s meant to destroy and remove the intruder. But this time, the threat is real, the response is fine-tuned, and it helps us stay healthy.

Other Roles

IgE may be crucial for our antiviral immune response, although this role is less studied. Scientists have identified human IgE antibodies against some respiratory viruses [12, 13].

Emerging evidence voices the importance of these antibodies in cancer prevention. They flag cancer cells and help our immune system remove them before they start spreading [14].

Indeed, higher levels of IgE may protect you against some types of cancer (more details below).

IgG vs. IgE

IgG immunoglobulins are our main antibodies, accounting for approximately 75% of the total amount. They shield us from infections by flagging all kinds of pathogens, such as bacteria, viruses, and fungi [15].

On the other hand, IgE is present in tiny amounts under normal conditions, and it’s specialized for parasitic infections.

IgE is involved in a common, more immediate allergic reaction (type 1). These reactions are either evident straight away or take up to 4 hours after exposure [16, 17].

IgG plays a central role in type 2 and 3 allergic reactions. These typically take a longer time to develop and include certain food and drug allergies [16, 17, 18].

IgG antibodies can also be anti-inflammatory and indicate tolerance (not sensitivity!) to specific foods. That’s why IgG-based food sensitivity tests don’t work [16].

IgE Blood Test

Test Types

You usually get an IgE blood test when you have recurring infections or to monitor immune disorders such as allergies.

New methods, such as ImmunoCAP (based on fluorescence), have been replacing the standard one called RAST (based on radioactive tracking).

These new methods are more sensitive and, besides total IgE levels, they also detect and measure specific IgE antibodies with up to 98% accuracy. This feature can aid in the diagnosis and management of allergies [19].

For example, testing for specific IgE might replace food challenges in diagnosing food allergies [20, 21].

On the other hand, total IgE is not a specific marker and can’t be used to diagnose a particular disease. It can, however, reveal certain clues, such as the risk of allergies, infections, and some chronic diseases [22].

Normal IgE Levels

IgE has the lowest concentration of all antibodies, especially in people without allergies. Normal values may vary in the scientific literature, but the usual reference range is 1.5-144 kU/L (IU/mL) [1, 23].

However, most labs have a limit of detection at 2-2.5 kU/L, under which levels are considered low [24, 25].

In studies on over 15K people, most healthy adults had IgE levels below 150 kU/L while the average value was around 27.2 kU/L [23, 26].

Men typically have higher IgE values than women, with up to 20 kU/L difference [27, 23, 26].

IgE levels increase through childhood, peak at 10-15 years of age, and then start dropping as we get older. In a study on over 500 preschool children, the average value was 80 kU/l 28, 29].

Other factors that influence IgE levels include [28, 30, 23, 31]:

  • Genetics
  • Race
  • Smoking
  • Alcohol consumption
  • Environmental factors
  • Immune status

We’ll dive into details about each one below.

In summary, different factors can influence immunoglobulin E levels, but most healthy adults will be in the range of 2-150 kU/L.

High IgE levels

Causes

1) Allergies

Allergies are the most common cause of elevated IgE. IgE increases in response to allergens, which are different for each person. For some, the triggers are dietary (food allergies), and for others they are seasonal (pollen allergies) [32].

Total IgE is not a sensitive lab parameter, but levels above 200 kU/L often indicate the presence or an increased risk of allergy [3, 33, 34].

According to a study on over 8K people, IgE > 100 kU/L increases the chance of atopy (allergic tendency). In 1300 Asian children, the limit was even lower: 77.7 kU/L [26, 35].

Eczema, Asthma, and Hay Fever

Atopic dermatitis or eczema generally causes the highest IgE levels, followed by asthma and hay fever. In a study on Chinese children, those with higher IgE also had more severe forms of eczema. In people with seasonal allergies, levels peak 4-6 weeks after pollen season [28, 36].

In over 1K people, those without allergies had the lowest average values (43.7 kU/L), followed by people with hidden allergies (213.8 kU/L) and asthma (626.6 kU/L) [27].

Hidden allergies are not accompanied by the typical symptoms. Apparently, even slightly elevated IgE might point to them.

A study on 562 children confirmed the connection between asthma and total IgE levels. It was a useful marker of lung sensitivity even in symptom-free children [37].

In 69 people with chronic hay fever, the average IgE levels were 378 kU/L – well above the normal range [38].

Food Allergies

Exposure to food allergens induces only a short-term increase in total IgE. It’s interesting that processed foods containing a particular allergen may cause 3-8 times higher levels compared with raw food allergens [32, 39].

Total IgE can’t detect food allergies, but tests that measure specific antibodies might do so [40].

Summary

Both an allergic predisposition and full-blown allergies are common causes of high IgE levels. The greater the exposure to the allergen, the more IgE will increase.

The use of total IgE for allergy diagnosis comes with notable limitations we’ll discuss below (see “Limitations and Caveats”).

2) Parasitic Infections

As mentioned, the primary role of IgE is to detect and help eliminate worms and other parasites from our bodies. In the absence of allergic tendencies and symptoms, parasitic infection is the most probable cause of high IgE [41, 42].

We produce some parasite-specific IgE immunoglobulins, but they aren’t always detectable in people with infections. Additional tests from a feces sample or blood smear may be necessary to confirm the diagnosis [43, 44].

3) Th2 Dominance

We still have a lot to learn about the clinical relevance of Th1/Th2-dominance, but they do have some distinct immune features [45].

Th2 immune cells produce IL-4, which is the primary signal for B cells to make IgE. Thus, Th2-dominant people are more likely to have higher levels of these antibodies [46, 30].

4) Race and Location

People with African ancestry and those living in tropical areas naturally have higher IgE [47, 3].

5) Rare Diseases

Hyper IgE syndromes (HIES) are rare disorders accompanied by high blood IgE. People suffering from them experience frequent skin and respiratory infections due to impaired immunity [48].

Job’s syndrome is the most common type which causes a range of bone and connective tissue abnormalities. IgE levels reach up to 2,000 kU/L, but they can drop (and even normalize) in adulthood [49].

A rare type of cancer called IgE multiple myeloma attacks plasma cells and causes increased production of these antibodies [50, 51].

Both conditions are uncommon, and there’s no reason to panic if your blood test revealed high IgE levels. A benign cause, such as allergen exposure is much more probable.

6) Genetics

According to a study on 877 Korean asthmatics, mutations (SNPs) in the following genes might increase total IgE levels [52]:

7) Other

Other conditions or lifestyle factors that may elevate IgE include:

  • Smoking [23, 27, 26]
  • Alcohol consumption [31, 53, 54]
  • Inflammatory bowel disease (IBD) [55, 56]
  • Bacterial and viral infections [57, 28, 58]
  • Lymphomas (lymphatic system cancers) [59, 56]
  • Nephrotic syndrome (kidney disorder) [60, 61, 62]

Symptoms

The symptoms of high IgE depend on the underlying cause. In most cases, the levels increase as a consequence of an allergic response with the symptoms such as [28, 32, 63]:

  • Itchy skin and eyes
  • Swelling
  • Coughing and sneezing
  • Nausea/vomiting
  • Difficulty breathing
  • Low blood pressure

If a parasitic infection spiked your IgE, it could manifest as [64, 65]:

  • Sudden weight loss
  • Anemia
  • Digestive issues
  • Fatigue

Health Risks

In over 1K older participants, high levels of IgE (≥267 kU/L) doubled the risk of cataracts, compared with average values (35-87 kU/L). Another similar study found a 37% increased risk [66, 67].

High IgE increased the risk of type 2 diabetes by 67-72% in 2 studies with 1,800 adults. It correlated with increased blood glucose and insulin resistance, regardless of other risk factors [68, 69].

However, type 2 diabetic patients had lower IgE levels compared with controls (22.5 vs. 43.3 kU/L) in a Japanese study while the average for type 1 diabetics was slightly higher (56.7 kU/L) [70].

One thing is for sure: allergic diseases can raise the risk of diabetes (both types) and vice versa, which might explain the connection between total IgE and diabetes in some patients [71, 72, 73].

Health Benefits

Although it usually signals an undesirable event, high IgE might actually protect you against some types of cancer.

A meta-analysis of 8 clinical trials (over 6K people) found a 27% reduced risk of brain tumors in people with high total IgE [74].

According to a comprehensive study on almost 38K individuals, elevated IgE has mixed effects on different types of cancer. After removing other factors, higher IgE predicted up to 56% lower risk of blood cancers [75].

IgE antibodies can help your immune system target and destroy cancer cells. New IgE-based cancer drugs have shown promising results in test tubes and animal trials. This kind of research belongs to a growing field of medicine called AllergoOncology [76, 14].

How to Reduce IgE Levels

1) Avoid Allergen Exposure

If you are allergic to a particular food or animal, avoiding them will help prevent allergic reactions. You may also want to clean your house and workspace regularly to get rid of dust mites or mold.

2) Increase Your Vitamin E Intake

A diet high in vitamin E will lower your IgE and relieve allergic reactions. Consume a variety of vitamin E-rich foods, such as [77, 78, 79]:

  • Sunflower seeds
  • Almonds
  • Hazelnuts
  • Spinach
  • Broccoli
  • Avocado

3) Refrain From Smoking and Alcohol Consumption

Studies voice a clear connection between smoking and high IgE levels. Same goes for alcohol consumption, even in moderate amounts [23, 27, 53, 54].

4) Consider Taking Supplements

A probiotic strain Bifidobacterium longum was able to reduce IgE and combat allergic reactions in multiple studies on mice and cells [80, 81, 82, 83].

Other strains that might help include B. breve, L. plantarum, and L. crispatus [84, 85, 86].

Besides probiotics, the following supplements may combat IgE overproduction:

Most studies have examined the effects on allergic responses, and it’s not clear whether these supplements can help reduce high IgE due to other causes.

5) Drug Treatment

Your doctor may prescribe immune-stabilizing drugs to manage your high IgE levels. Treatment will depend on the underlying disease and your overall symptoms.

For example, you may get an inhaled medication for asthma, creams for eczema, or nose sprays for hay fever.

These drugs may contain corticosteroids (to reduce swelling), antihistamines (to block histamine-triggered inflammation), or decongestants (to relieve nose stuffiness) [92].

Additionally, some IgE-targeted drugs include:

  • Omalizumab, a biological drug that contains anti-IgE antibodies. These bind to IgE and remove it from the bloodstream, thus reducing allergic response. The FDA approved this drug for severe asthma and chronic hives (urticaria) [93, 94].
  • Nedocromil sodium and disodium cromoglycate (cromolyn sodium), which belong to a group of drugs called mast cell stabilizers. They are available as inhalers, nasal sprays, and eye drops for asthma and seasonal allergies [95, 96, 97].

Low IgE Levels

Causes and Symptoms

IgE levels can be quite low in the absence of the above conditions, and this usually doesn’t indicate any disorder.

Selective IgE deficiency (IgE hypogammaglobulinemia) is a type of immunodeficiency with the levels of this antibody below the limit of detection: <2-2.5 kU/L. It may cause the following symptoms [98, 25]:

If the levels of other antibodies (IgG, IgM, IgA) are low, common variable immunodeficiency (CVID) is the most probable cause. People with CVID have frequent respiratory and other infections that may lead to tissue damage [99, 100, 101].

The lack of antibodies and immunodeficiency can also occur due to [102, 103]:

  • Drug treatment
  • Kidney and gut disorders
  • Cancer
  • Severe burns

IgE is low in such cases but usually above 2 kU/L [99].

Ataxia-telangiectasia is a rare inherited immunodeficiency with low IgE levels while other antibodies are in the normal range. It causes “spider veins” and neurological disorders [104, 105].

Risks

Immunodeficient people with low IgE levels have a higher risk of infections, inflammatory diseases, and cancer [25, 105, 101].

Although autoimmunity and immunodeficiency may seem like opposite conditions, they are actually “two sides of the same coin” [106].

In a study with over 1K people, those with IgE deficiency had an increased risk of [98]:

  • High blood pressure, 2-fold
  • Heart disease, 3-fold
  • Stroke, 6-fold

In more than 3K people, IgE deficiency increased the risk of H. pylori infection by 43%. These patients also had more frequent stomach inflammation or gastritis (28%) and ulcers (47%) [107].

As mentioned above, high IgE may raise the risk of cataracts in the elderly. Same goes for low levels as those with ≤35 kU/L had a 67% higher risk [66].

Limitations

As many different conditions can increase total IgE, it’s not suitable for diagnosing a particular disease or even allergies in general [27, 108].

Low levels are a bit more specific, but they too can’t confirm the exact type of immunodeficiency without additional tests [22, 103].

Being unspecific, the cost-effectiveness and the routine clinical use of total IgE blood tests is questionable [109].

When it comes to allergies, skin prick and patch tests remain the first choice. They are sensitive, suitable for most allergens, more convenient, and cheaper than a total IgE test [38, 110].

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Takeaway

Immunoglobulin E (IgE) is an antibody that fights parasitic infections, microbes, and cancer cells. It is also involved in allergic reactions. This makes allergies and parasitic infections the two most common causes of high total IgE (>150 kU/L). High IgE may increase your risk of cataracts and diabetes, but it may protect you against brain and blood cancer.

To lower your IgE naturally, increase vitamin E intake and refrain from smoking and alcohol consumption. Consider supplementing with probiotics, fish oil, and flavonoids.

Low or undetectable IgE (<2-2.5 kU/L) usually points to an immunodeficiency disorder that can cause frequent infections, gut disorders, and autoimmune diseases.

About the Author

Aleksa Ristic, MSc (Pharmacy)

MS (Pharmacy)

Aleksa received his MS in Pharmacy from the University of Belgrade, his master thesis focusing on protein sources in plant-based diets.

 

Aleksa is passionate about herbal pharmacy, nutrition, and functional medicine. He found a way to merge his two biggest passions—writing and health—and use them for noble purposes. His mission is to bridge the gap between science and everyday life, helping readers improve their health and feel better.

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