Lab result explainedInflammationLast updated November 10, 2026

IgE blood test: what high total IgE levels mean for allergies, asthma and eczema

Immunoglobulin E (IgE) · Total IgE (often with specific IgE allergy panel) · reported in IU/mL (identical to kU/L; 1 IU/mL is about 2.4 ng/mL)

Immunoglobulin E (IgE) is the antibody class behind immediate allergic reactions, and a total IgE blood test measures the overall amount of it circulating in your blood. In most adults the result is under about 100 IU/mL. People with allergic rhinitis, asthma or eczema tend to run higher, often 150 to 1,000 IU/mL, and values in the thousands are seen in severe atopic dermatitis, allergic bronchopulmonary aspergillosis, parasitic worm infections and a few rare immune disorders.

Total IgE is a blunt instrument. Roughly a quarter of people with proven allergies have a total IgE in the normal range, and many people with a mildly high value have no allergy at all, so a total IgE on its own neither confirms nor rules out allergic disease. The tests that identify what you react to are the specific IgE tests (ImmunoCAP or similar), which measure IgE directed against individual allergens such as dust mite, cat, grass pollen, peanut or egg, and skin-prick testing.

Where total IgE earns its place is in context: deciding whether an asthma patient is eligible for the anti-IgE drug omalizumab (the US label uses 30 to 700 IU/mL), screening for allergic bronchopulmonary aspergillosis in asthma and cystic fibrosis (over 1,000 IU/mL is a diagnostic criterion), flagging a possible parasitic infection after travel, and in children with recurrent infections and severe eczema, where a value over 2,000 IU/mL raises the question of hyper-IgE syndrome.

IgE at a glance

What it is: the total amount of immunoglobulin E, the antibody that triggers mast cells and histamine release in allergic reactions, measured in international units per millilitre (IU/mL, the same as kU/L).
Normal (adults): under about 100 IU/mL at most labs (some use 87, 114 or 150). Children have lower limits that rise with age: under about 15 in infants, 60 at age 5, 200 in teenagers.
High IgE most often means atopy: allergic rhinitis, allergic asthma, eczema or food allergy. Values over 1,000 IU/mL suggest severe eczema, allergic bronchopulmonary aspergillosis or a parasitic infection; over 2,000 with recurrent infections raises the possibility of hyper-IgE syndrome.
A normal total IgE does not rule out allergy; about one in four people with confirmed allergy have a normal total.
Low IgE is not usually a problem; a very low or undetectable value is occasionally a clue to an antibody deficiency.
Next step: specific IgE tests or skin-prick testing to the allergens that fit your history; if there is no allergic history, a CBC with eosinophil count, a stool test for parasites if you have travelled, and for asthma patients, consideration of Aspergillus-specific IgE.

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What IgE measures

IgE is made by plasma cells after a type of helper T cell (Th2) steers the immune response toward allergy, a process driven by the cytokines IL-4 and IL-13. Once made, IgE binds tightly to receptors on mast cells in the skin, airways and gut and on basophils in the blood. When an allergen later cross-links two IgE molecules on a mast cell, the cell releases histamine, leukotrienes and tryptase within minutes, producing hives, sneezing, wheeze or, at the extreme, anaphylaxis. The same pathway evolved to fight parasitic worms, which is why helminth infections push IgE to very high levels.

IgE is the scarcest immunoglobulin in blood: a normal adult has about 100,000 times less IgE than IgG. The laboratory measures it with an immunoassay (usually fluorescence enzyme immunoassay, such as ImmunoCAP) calibrated to a World Health Organization reference standard, which is why results are reported in IU/mL or kU/L rather than mg/dL; 1 IU is about 2.4 nanograms. The free IgE in serum has a half-life of only about 2 days, though IgE bound to mast cells persists for weeks.

Total IgE rises through childhood, peaks between about 10 and 15 years of age and then falls slowly through adult life. It is higher in men than women, higher in smokers, and strongly influenced by genes, so the reference range is age-specific and wide. Specific IgE tests measure IgE against one allergen at a time and are reported in kUA/L in classes: under 0.35 is class 0 (negative or very low), 0.35 to 0.69 class 1, 0.70 to 3.49 class 2, 3.5 to 17.4 class 3, 17.5 to 49.9 class 4, 50 to 99.9 class 5 and 100 or more class 6. The higher the class, the more likely a reaction, but a positive specific IgE shows sensitization, not necessarily clinical allergy.

Normal range for IgE

Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.

Group	Typical range (IU/mL (identical to kU/L; 1 IU/mL is about 2.4 ng/mL))	Notes
Adults	Below about 100 IU/mL	Some labs use upper limits of 87, 114 or 150 IU/mL. Use the limit printed on your report; labs and assays differ.
Newborns (cord blood)	Below about 1.5 IU/mL	IgE does not cross the placenta; a raised cord-blood IgE was once used to predict atopy in the baby.
Infants under 1 year	Below about 15 IU/mL	Rises steadily through the first years of life.
Children 1 to 5 years	Below about 60 IU/mL	Children with eczema or food allergy commonly exceed this.
Children 6 to 9 years	Below about 90 IU/mL
Children 10 to 15 years	Below about 200 IU/mL	Total IgE peaks in the early teens, then falls slowly through adult life.
Typical range in allergic rhinitis, asthma or eczema	About 150 to 1,000 IU/mL	Overlaps widely with normal. About 20 to 30 percent of people with proven allergy have a total IgE under 100.
Omalizumab eligibility (asthma)	30 to 700 IU/mL (US label; up to 1,500 in Europe)	Dose is set from total IgE and body weight before treatment starts. Total IgE rises after starting omalizumab and cannot be re-used for dosing.
Allergic bronchopulmonary aspergillosis (ABPA)	Above 500 IU/mL	2024 ISHAM criterion for both asthma and cystic fibrosis (the older asthma cut-off was 1,000). Lower values can still fit when other criteria are met, and total IgE alone never diagnoses ABPA. A value above 2,000 with recurrent skin and lung infections and severe eczema suggests hyper-IgE syndrome.

High IgE

A high total IgE most often means your immune system is skewed toward allergy. In an adult with hay fever, asthma or eczema a result of 150 to 1,000 IU/mL is expected and adds little on its own; it confirms a tendency rather than naming a trigger. The next question is always which allergens are responsible, which is answered by specific IgE testing or skin-prick tests chosen to match your symptoms, not by the total.

The size of the number matters at the upper end. Values above 1,000 IU/mL are unusual in simple hay fever and point toward severe atopic dermatitis (where values of 5,000 to 20,000 are common), allergic bronchopulmonary aspergillosis in someone with asthma or cystic fibrosis, a parasitic infection such as hookworm, strongyloides, ascaris or schistosomiasis, or eosinophilic granulomatosis with polyangiitis. Above 2,000 IU/mL in a child with recurrent boils, pneumonias and eczema from infancy raises the rare hyper-IgE (Job) syndrome, in which values often exceed 10,000.

A mildly high IgE in someone with no allergic symptoms is common and usually needs no action. Smoking, a family history of atopy, eczema in childhood that has settled, and some chronic skin and infectious conditions all nudge it up. If the eosinophil count is also raised, or you have travelled to the tropics, a stool examination for parasites is reasonable before concluding it is allergic.

Common causes

Allergic rhinitis, allergic asthma and allergic conjunctivitis
The most common reasons. Sensitization to dust mite, pollens, animal dander and molds drives IgE production; total IgE is typically 100 to 500 IU/mL, higher when several allergens are involved or asthma is poorly controlled.
Atopic dermatitis (eczema)
Produces the highest IgE levels of any common condition. Moderate to severe eczema often runs 1,000 to 10,000 IU/mL, and the level correlates loosely with severity. About 20 percent of people with eczema have a normal IgE (so-called intrinsic eczema).
Food allergy
IgE-mediated allergy to peanut, tree nuts, egg, milk, shellfish, fish, wheat or soy raises total IgE, particularly in children with multiple food allergies and eczema. The diagnosis rests on the history plus specific IgE or skin testing, not the total.
Parasitic worm infections
Hookworm, roundworm (Ascaris), Strongyloides, schistosomiasis, filariasis and toxocara trigger IgE levels of 1,000 to over 10,000 IU/mL, usually with a raised eosinophil count. Consider after travel or residence in the tropics, or unexplained eosinophilia.
Allergic bronchopulmonary aspergillosis (ABPA)
An exaggerated allergic response to Aspergillus in the airways of people with asthma or cystic fibrosis; total IgE above 500 IU/mL (2024 ISHAM criteria) with Aspergillus-specific IgE and eosinophilia is diagnostic. Worsening asthma with brown mucus plugs and lung infiltrates is the typical picture.
Hyper-IgE syndromes
Rare inherited immune deficiencies (STAT3 loss-of-function, DOCK8 deficiency) with IgE above 2,000 and often above 10,000 IU/mL, recurrent staphylococcal skin abscesses, pneumonias with lung cysts, severe eczema and, in STAT3 disease, retained baby teeth and characteristic facial features.
Eosinophilic granulomatosis with polyangiitis (EGPA)
A vasculitis arising in adults with asthma and nasal polyps; IgE is commonly raised with a high eosinophil count, sinus disease and nerve or skin involvement.
Smoking
Current smokers have total IgE levels about 30 to 50 percent higher than never-smokers in population studies, independent of allergy. Levels fall slowly after stopping.
Other immune and inflammatory conditions
Nephrotic syndrome, Kimura disease, bullous pemphigoid, chronic urticaria, HIV infection, Hodgkin lymphoma and the rare IgE myeloma can all raise total IgE, usually modestly except in IgE myeloma.
Omalizumab (anti-IgE) treatment
A laboratory artefact to know about: standard assays measure IgE bound to omalizumab as well as free IgE, so total IgE rises 3 to 5 fold after starting the drug and stays high for months after stopping. A level measured on treatment should not be used to judge allergy or to re-dose.

Symptoms that can go with it

Often none; a high IgE is a tendency, not a disease, and many people with mildly raised values feel well
Sneezing, runny or blocked nose, itchy watery eyes, especially seasonally or around animals or dust
Wheeze, chest tightness, cough and breathlessness with allergic asthma
Dry, itchy, inflamed skin in the creases of elbows and knees, hands or face with eczema
Hives, lip or tongue swelling, vomiting or wheeze within minutes to 2 hours of eating a particular food
Worsening asthma with fever, brown sputum plugs and lung shadowing in ABPA
Abdominal pain, diarrhea, cough or an itchy rash after tropical travel, with a raised eosinophil count, in parasitic infection
Recurrent skin abscesses and pneumonias from infancy with severe eczema in hyper-IgE syndrome

Low IgE

A low total IgE is rarely a cause for concern. About 5 percent of healthy adults have a total IgE below 10 IU/mL simply because they are not atopic, and many laboratories do not even print a lower limit of normal. A low IgE makes IgE-mediated allergy less likely but does not exclude it, because a person can have a strongly positive specific IgE to one allergen with a low total.

A very low or undetectable total IgE (under about 2.5 IU/mL) is sometimes a clue to a broader antibody deficiency. In common variable immunodeficiency, IgE is usually undetectable along with low IgG and IgA, and selective IgE deficiency has been associated in some studies with recurrent sinus and chest infections, autoimmune disease and chronic fatigue, though it is not an accepted immune deficiency in its own right. If IgE is undetectable and you have recurrent infections, measuring IgG, IgA and IgM is the sensible next step.

Common causes

Non-atopic constitution
The usual explanation. People without allergic tendencies, particularly older adults, often have total IgE under 20 IU/mL.
Common variable immunodeficiency and other antibody deficiencies
Low IgG and IgA with absent IgE and a history of recurrent bacterial sinus, ear and chest infections; confirmed by immunoglobulin levels and vaccine responses.
Selective IgE deficiency
Total IgE under 2.5 IU/mL with other immunoglobulins normal; reported in 2 to 3 percent of some clinic populations and associated with recurrent infections and autoimmunity, though its significance is debated.
Ataxia-telangiectasia and other rare primary immunodeficiencies
IgE is low or absent alongside low IgA in these inherited conditions, which present in childhood with infections and neurological signs.
Immunosuppressive treatment
High-dose corticosteroids, rituximab, cyclophosphamide and other agents that suppress B cells reduce all immunoglobulins including IgE.
Myeloma of another immunoglobulin class
In IgG or IgA myeloma, the normal immunoglobulins including IgE are suppressed (immunoparesis).

Symptoms that can go with it

None in the great majority of people
Recurrent sinus infections, ear infections, bronchitis or pneumonia if the low IgE is part of a wider antibody deficiency
Chronic diarrhea, poor growth in children or unexplained autoimmune disease in the same setting

Read it alongside

Specific IgE panel (ImmunoCAP) or skin-prick testing — identifies the actual allergens; the total IgE only says that the allergic tendency exists.
Eosinophil count — raised with allergy, ABPA, EGPA and parasites; a high IgE with eosinophils over 1,500/µL needs a cause found.
Aspergillus fumigatus specific IgE and IgG — ordered in asthma or cystic fibrosis when total IgE is above 500 IU/mL to diagnose ABPA.
Tryptase — raised persistently in mast cell disorders and transiently after anaphylaxis; helps when reactions are severe but IgE tests are negative.
IgG, IgA and IgM — checked when IgE is undetectable or very high in a child with infections, to characterise an immune deficiency.
Stool ova and parasites, Strongyloides serology — when IgE and eosinophils are both high after travel or in people from endemic areas.
Spirometry and fractional exhaled nitric oxide — define asthma and its allergic (eosinophilic) type alongside IgE.
Component-resolved specific IgE (for example Ara h 2 for peanut) — separates true allergy from cross-reactive pollen sensitization when the standard specific IgE is positive.

What usually happens next

Match the result to your history: a total IgE of 150 to 1,000 IU/mL with hay fever, asthma or eczema needs no further explanation, but specific IgE or skin tests chosen for your symptoms will tell you what to avoid or treat.
A positive specific IgE means sensitization; whether it matters depends on whether you react on exposure. Food allergy in particular should not be diagnosed, or foods removed from a child's diet, on a blood test alone.
If total IgE is above 500 IU/mL and you have asthma or cystic fibrosis, ask about Aspergillus-specific IgE, an eosinophil count and a chest X-ray to look for ABPA.
If IgE and eosinophils are high with no allergic history, expect stool parasite tests and Strongyloides serology, especially after tropical travel.
Do not use a total IgE measured while on omalizumab to judge anything; the drug inflates it.
For an undetectable IgE with recurrent infections, ask for IgG, IgA and IgM levels and a referral to an immunologist if they are low.

Diet, lifestyle and natural levers with evidence

What can move IgE once the cause is known. Nothing here replaces finding the cause.

Allergen avoidance guided by test results

Moderate evidence

Avoidance works best when it is specific and achievable. Removing a pet from the home reduces symptoms and medication use in people sensitized to it, and a Cochrane review of house-dust-mite control measures found impermeable bedding alone made little difference to asthma, whereas combined measures in children with mite-sensitive asthma cut emergency visits in some trials. Total IgE itself falls only slowly, by perhaps 20 to 30 percent over a year or more of avoiding a major allergen.

Stop smoking

Moderate evidence

Smokers have total IgE levels roughly 30 to 50 percent higher than never-smokers in large population studies, and ex-smokers sit between the two, with levels drifting down over years after quitting. Smoking also worsens asthma control and blunts the response to inhaled steroids, so stopping improves the condition behind the number as well as the number.

Early introduction of allergenic foods in infancy

Strong evidence

In the LEAP trial, infants at high risk of peanut allergy (severe eczema, egg allergy or both) who ate peanut regularly from 4 to 11 months of age had an 81 percent lower rate of peanut allergy at age 5 than those who avoided it, and they developed less peanut-specific IgE. Guidelines in the US, UK and Australia now recommend introducing peanut and egg around 4 to 6 months rather than delaying.

Infants with severe eczema or existing food allergy should have testing or supervised first exposure arranged by a clinician before peanut is introduced.

Vitamin D (when deficient) for asthma control

Moderate evidence

A 2017 individual-participant meta-analysis of 7 randomised trials found vitamin D supplementation reduced the rate of asthma attacks needing steroids by about 30 percent overall, with the benefit concentrated in people whose starting level was under 25 nmol/L (10 ng/mL). Vitamin D has not been shown to lower total IgE in adults; its value is in reducing exacerbations in people who are deficient.

Doses above 4,000 IU a day long term can raise calcium; check a 25-hydroxyvitamin D level rather than guessing.

Fish oil in pregnancy to reduce childhood wheeze

Moderate evidence

In a Danish randomised trial of 736 pregnant women, 2.4 g a day of EPA plus DHA from week 24 reduced persistent wheeze or asthma in the children at age 5 from 23.7 to 16.9 percent, a 31 percent relative reduction, with the largest effect in mothers whose own omega-3 levels were low. Effects on the children's IgE levels were not significant, and fish oil taken by adults with established allergy has little measurable effect on IgE.

Probiotics in pregnancy and infancy for eczema prevention

Preliminary evidence

Meta-analyses of trials giving Lactobacillus rhamnosus GG or mixed strains to mothers in late pregnancy and to infants find a reduction in eczema of around 20 to 30 percent by age 2, which is why the World Allergy Organization conditionally suggests them in high-risk families. The effect on IgE-mediated allergy, asthma and total IgE is not established, and results differ between strains.

When to see a clinician promptly

Any reaction with throat tightness, difficulty breathing, widespread hives with dizziness or faintness, or swelling of the tongue or lips: this is anaphylaxis and needs emergency care (call emergency services, use an epinephrine auto-injector if you have one).
Asthma that is getting worse despite treatment, with brown mucus plugs, fever or new lung shadowing on a chest X-ray, particularly if total IgE is above 500 IU/mL (possible ABPA).
A total IgE above 1,000 IU/mL with no clear allergic explanation, or any high IgE with an eosinophil count above 1,500/µL, which needs parasites, EGPA and other causes excluded.
A child with IgE above 2,000 IU/mL and recurrent boils, pneumonias or severe eczema since infancy (possible hyper-IgE syndrome).
An undetectable IgE with recurrent sinus, ear or chest infections, which may indicate a broader antibody deficiency.
Suspected food allergy in a child: testing and any elimination diet should be supervised so that foods are not removed unnecessarily.

Frequently asked questions

What is a normal IgE level?

In adults, most laboratories consider total IgE normal below about 100 IU/mL, though upper limits of 87, 114 or 150 are also used, so check your report. Children have lower ranges that rise with age: roughly under 15 IU/mL in the first year, under 60 by age 5, under 90 by age 9 and under 200 in the early teens, after which levels gradually fall into adulthood.

Is an IgE of 200, 500 or 1,000 high?

All three are above the adult reference range, but they mean different things. An IgE of 200 is a mild rise seen in many people with hay fever, mild asthma or no symptoms at all. An IgE of 500 is typical of established allergic asthma, several allergen sensitizations or eczema. An IgE of 1,000 or more is unusual for ordinary allergy and prompts a look for severe eczema, allergic bronchopulmonary aspergillosis, parasites or, rarely, an immune disorder.

Can I have allergies with a normal IgE?

Yes. Around 20 to 30 percent of people with proven allergic disease have a total IgE in the normal range, because the total reflects IgE to everything, and a strong response to a single allergen such as cat or peanut can sit inside a normal total. If your symptoms suggest allergy, specific IgE tests or skin-prick tests to the relevant allergens are the tests that matter.

What does the IgE test for allergies actually show?

There are two kinds. Total IgE shows the overall allergic tendency. Specific IgE tests measure antibodies against individual allergens and are reported in kUA/L and classes 0 to 6; a result of 0.35 or above is considered positive. A positive specific IgE means you are sensitized, which raises the likelihood of a reaction but does not prove one; the diagnosis comes from putting the test together with what happens when you are exposed.

What causes very high IgE levels?

Severe atopic dermatitis is the most common cause of IgE in the thousands, followed by allergic bronchopulmonary aspergillosis in people with asthma or cystic fibrosis, parasitic worm infections, eosinophilic granulomatosis with polyangiitis and the rare hyper-IgE syndromes, in which levels usually exceed 2,000 and often 10,000 IU/mL. IgE myeloma is extremely rare. A very high level in someone without eczema deserves an eosinophil count and a specialist opinion.

Do I need to fast for an IgE blood test?

No. IgE is not affected by food, time of day or recent meals. Antihistamines do not interfere with the blood test (they do suppress skin-prick tests, so stop them for 3 to 7 days before skin testing if asked). Omalizumab does interfere, raising measured total IgE several-fold, and oral steroids can lower IgE slightly over time.

How can I lower my IgE levels naturally?

Slowly and only partly. Avoiding the allergens you are sensitized to, stopping smoking and treating eczema well all lower total IgE over months, typically by a modest fraction. Allergen immunotherapy (allergy shots or tablets) is the only treatment that reshapes the response over years, and it initially raises specific IgE before lowering it. Supplements marketed to lower IgE have not shown that effect in trials; the aim is to control the allergic disease rather than the number.

Is high IgE the same as being immunocompromised?

No. A high IgE usually reflects an over-active allergic response, not a weak immune system. The exception is the hyper-IgE syndromes, rare inherited disorders in which an extremely high IgE sits alongside a genuine immune deficiency with recurrent abscesses and pneumonias; these are diagnosed in childhood by an immunologist, and ordinary allergy-related IgE elevations do not carry that risk.

References

Allergy blood test. MedlinePlus, US National Library of Medicine (2023)View source
Allergy skin tests and allergy blood tests. Mayo Clinic (2024)View source
Wittig HJ, Belloit J, De Fillippi I, Royal G. Age-related serum immunoglobulin E levels in healthy subjects and in patients with allergic disease. Journal of Allergy and Clinical Immunology (1980)
Carosso A, Bugiani M, Migliore E, Antò JM, DeMarco R. Reference values of total serum IgE and their significance in the diagnosis of allergy in young European adults. International Archives of Allergy and Immunology (2007)
Hamilton RG, Williams PB. Human IgE antibody serology: a primer for the practicing North American allergist/immunologist. Journal of Allergy and Clinical Immunology (2010)
Agarwal R, Chakrabarti A, Shah A, et al.. Allergic bronchopulmonary aspergillosis: review of literature and proposal of new diagnostic and classification criteria. Clinical and Experimental Allergy (2013)
Freeman AF, Holland SM. The hyper-IgE syndromes. Immunology and Allergy Clinics of North America (2008)
Hyperimmunoglobulin E syndrome. Merck Manual Professional Version (2024)
Du Toit G, Roberts G, Sayre PH, et al.. Randomized trial of peanut consumption in infants at risk for peanut allergy (LEAP). New England Journal of Medicine (2015)
Jolliffe DA, Greenberg L, Hooper RL, et al.. Vitamin D supplementation to prevent asthma exacerbations: a systematic review and meta-analysis of individual participant data. Lancet Respiratory Medicine (2017)
Bisgaard H, Stokholm J, Chawes BL, et al.. Fish oil-derived fatty acids in pregnancy and wheeze and asthma in offspring. New England Journal of Medicine (2016)
Omalizumab (Xolair) prescribing information. US Food and Drug Administration (2024)

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This page is educational and is not medical advice or a diagnosis. Lab results have to be interpreted together with your history, symptoms and other results by a clinician who knows you. Do not start or stop a supplement to change a lab value before the cause is known.