Food allergy: the basics, for clinicians

This is the clinician view. It keeps every sentence of the plain guide and adds, for each section, the study design and citations of its sources, exact figures, and label wording quoted whole, marked For clinicians. Every added sentence is cited and checked like the rest. Back to plain language.

In short

US guidelines describe two kinds of food allergy: reactions driven by the allergy antibody IgE, and reactions that work another way (non-IgE).E2Good¹
About 1 in 10 US adults has a convincing food allergy, while nearly 1 in 5 believes they have one.E2Good²
Food intolerance, lactose malabsorption, celiac disease and spoiled-fish poisoning can all be mistaken for food allergy.E1Strong^1,3,4
Many children outgrow milk and egg allergy, often in later childhood; peanut and tree nut allergy are outgrown less often.E2Good^5,6,7,8

How sure each claim is:E1Strong E2Good Official text Review What the grades meanUnderlined words open a definition

What is a food allergy?

The US national guidelines for food allergy give a consensus definition. They cover two kinds of reaction. Some are driven by IgE, the antibody behind most quick allergic reactions. Others are not (called non-IgE-mediated).E2Good¹

In a large German study that confirmed reactions with blinded food challenges, about 3.6% of people had a real adverse reaction to food. Of these, 2.5% were IgE-mediated and 1.1% were not.E2Good⁹

The same study found that about 35% of people said they had reacted to a food at some point in life. That is far more than the challenges confirmed.E2Good⁹

For clinicians

The NIAID expert panel's consensus definition, quoted as written:

A food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.
Quoted word for word from Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel (full text) E2Good¹⁰

On sensitization, the panel wrote:

Because individuals can develop allergic sensitization (as evidenced by the presence of allergen-specific IgE (sIgE)) to food allergens without having clinical symptoms on exposure to those foods, an sIgE-mediated FA requires both the presence of sensitization and the development of specific signs and symptoms on exposure to that food. Sensitization alone is not sufficient to define FA.
Quoted word for word from Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel (full text) E2Good¹⁰

Zuberbier's Berlin population study (mean age 41 years) confirmed reactions by double-blind, placebo-controlled food challenge. Point prevalence was 3.6% across all ages (95% CI 3.0% to 4.2%) and 3.7% in adults aged 18 to 79 (95% CI 3.1% to 4.4%). Of those affected, 60.6% were female.E2Good⁹

Self-reported lifetime prevalence of any adverse reaction to food in the same population was 34.9%.E2Good⁹

The evidence in this section (3 sources)

Source	Design	Grade	Citations (NIH iCite)
1 NIAID-Sponsored Expert Panel, J Allergy Clin Immunol, 2010	Guideline	E2Good	1,036 (RCR 34.84)
9 Zuberbier T, Allergy, 2004	Observational study	E2Good	208 (RCR 6.99)
10 Boyce JA, 2010	Guideline	E2Good	Not tracked

How common is food allergy in adults?

A national US survey estimated that 10.8% of adults, more than 26 million people, have a convincing food allergy. Nearly 19% of adults believe they have one.E2Good²

The most common adult food allergies in that survey were shellfish (2.9%), milk (1.9%), peanut (1.8%), tree nuts (1.2%) and fin fish (0.9%).E2Good²

The authors concluded that adults with a suspected food allergy need proper confirmatory testing and counseling. The aim is that foods are not avoided for no reason and quality of life is not harmed.E2Good²

For clinicians

Gupta's national survey estimated convincing food allergy in 10.8% of US adults (95% CI 10.4% to 11.1%), while 19.0% (95% CI 18.5% to 19.5%) self-reported one.E2Good²

By food: shellfish 2.9% (95% CI 2.7% to 3.1%), milk 1.9% (1.8% to 2.1%), peanut 1.8% (1.7% to 1.9%), tree nut 1.2% (1.1% to 1.3%) and fin fish 0.9% (0.8% to 1.0%).E2Good²

The evidence in this section (1 source)

Source	Design	Grade	Citations (NIH iCite)
2 Gupta RS, JAMA Netw Open, 2019	Observational study	E2Good	769 (RCR 42.2)

What else can look like a food allergy?

The US guidelines note that people often confuse reactions that are not allergic, such as food intolerance, with food allergy. This makes the public believe food allergy is more common than it is.E2Good¹

Lactose malabsorption. Around two thirds of the world's adults do not fully absorb lactose, the sugar in milk, with wide differences between regions.E1Strong³
Celiac disease. An immune reaction to gluten that affects about 1% of people in most populations. It ranges from severe malabsorption to almost no symptoms.Review¹¹
Scombroid poisoning. Spoiled fish such as tuna and mackerel can carry large amounts of histamine. Flushing and headache began 10 to 30 minutes after eating the fish in the study that identified histamine as the cause.E2Good⁴
Hives. Hives are common: about 1 in 5 people has acute hives at some point in life.E2Good¹²

Because so many things can look alike, the German study concluded that a step-by-step approach that includes food challenges is needed to confirm the diagnosis.E2Good⁹

For clinicians

Standardized for country size, Storhaug's meta-analysis put global lactose malabsorption at 68% (95% CI 64 to 72). Estimates ranged from 28% (19 to 37) in western, southern and northern Europe to 70% (57 to 83) in the Middle East.E1Strong³

Diagnosis of celiac disease requires duodenal villous atrophy, and most patients have circulating antibodies against tissue transglutaminase. In children, European guidelines allow a diagnosis without biopsy when strict symptomatic and serological criteria are met.Review¹¹

In Morrow's study, scombroid poisoning was associated with urinary excretion of histamine in quantities far exceeding those needed to produce toxicity, identifying histamine as the responsible toxin.E2Good⁴

The evidence in this section (6 sources)

Source	Design	Grade	Citations (NIH iCite)
1 NIAID-Sponsored Expert Panel, J Allergy Clin Immunol, 2010	Guideline	E2Good	1,036 (RCR 34.84)
3 Storhaug CL, Lancet Gastroenterol Hepatol, 2017	Meta-analysis	E1Strong	249 (RCR 12.22)
11 Lebwohl B, Lancet, 2018	Expert review	Review	738 (RCR 38.21)
4 Morrow JD, N Engl J Med, 1991	Observational study	E2Good	163 (RCR 7.06)
12 Zuberbier T, Allergy, 2026	Guideline	E2Good	42 (RCR 32.51)
9 Zuberbier T, Allergy, 2004	Observational study	E2Good	208 (RCR 6.99)

Do children outgrow food allergies?

Some do, and it depends on the food. In one large clinic group, milk allergy had resolved in 19% of children by age 4 and 42% by age 8. It had resolved in 64% by age 12 and 79% by age 16.E2Good⁵

In a similar study, egg allergy resolved in 4% by age 4 and 12% by age 6. It resolved in 37% by age 10 and 68% by age 16. Most children with egg allergy are likely to outgrow it by late childhood.E2Good⁶

Peanut allergy was long thought to be rarely outgrown. One study found it was outgrown in about 21.5% of patients. A population study in Australia found it resolved in 22% of children by age 4.E2Good^7,13

About 9% of people with tree nut allergy outgrow it, including some who had severe reactions before.E2Good⁸

Many children with milk or egg allergy can eat these foods when they are extensively heated, as in baked goods. About 75% with milk allergy tolerated heated milk in one study. Most with egg allergy tolerated heated egg in another.E2Good^14,15

European guidelines describe checking children with food allergy again over time, with allergy tests or supervised food challenges. The aim is that a food can return to the diet if tolerance has developed.E2Good¹⁶

For clinicians

In Skripak's cohort, the prognosis of cow's milk allergy was worse than previously reported, and cow's milk IgE level was highly predictive of outcome.E2Good⁵

Savage's Kaplan-Meier analysis of egg allergy predicted resolution in 68% by age 16. Patients with egg IgE greater than 50 kU/L were unlikely to develop egg tolerance.E2Good⁶

In Skolnick's peanut study, 67% of patients with peanut IgE below 2 kU(A)/L and 61% with levels below 5 kU(A)/L had negative challenges. The authors advised that patients with low peanut IgE be offered a challenge in a medical setting.E2Good⁷

In Peters' population-based cohort, peanut allergy resolved in 22% (95% CI 14% to 31%) by age 4. At that age, a skin prick test of 8 mm or more, or sIgE of 2.1 kU/L or more, had a 95% positive predictive value for persistent peanut allergy.E2Good¹³

In Fleischer's tree nut study, 9 of 20 patients who had previously reacted to a tree nut passed challenges, so 9 of 101 (8.9%; 95% CI 4% to 16%) with prior reactions outgrew the allergy. The authors suggested considering challenge from age 4 when all tree nut IgE levels are 5 kU(A)/L or less.E2Good⁸

In Nowak-Wegrzyn's milk study, 68 subjects tolerated extensively heated milk only, 23 reacted to heated milk, and 9 tolerated both heated and unheated milk.E2Good¹⁴

In Lemon-Mulé's egg study, 64 of 117 subjects tolerated heated egg, 23 tolerated regular egg and 27 reacted to heated egg. Continued ingestion of heated egg was associated with immunologic changes that paralleled those of developing tolerance to regular egg.E2Good¹⁵

The evidence in this section (8 sources)

Source	Design	Grade	Citations (NIH iCite)
5 Skripak JM, J Allergy Clin Immunol, 2007	Observational study	E2Good	538 (RCR 16.11)
6 Savage JH, J Allergy Clin Immunol, 2007	Observational study	E2Good	383 (RCR 11.06)
7 Skolnick HS, J Allergy Clin Immunol, 2001	Observational study	E2Good	382 (RCR 10.81)
13 Peters RL, J Allergy Clin Immunol, 2015	Observational study	E2Good	170 (RCR 7.13)
8 Fleischer DM, J Allergy Clin Immunol, 2005	Observational study	E2Good	197 (RCR 5.88)
14 Nowak-Wegrzyn A, J Allergy Clin Immunol, 2008	Observational study	E2Good	390 (RCR 12.18)
15 Lemon-Mulé H, J Allergy Clin Immunol, 2008	Observational study	E2Good	331 (RCR 10.63)
16 Santos AF, Allergy, 2023	Guideline	E2Good	265 (RCR 42.15)

How is food allergy managed?

After an IgE-mediated food allergy is confirmed, European guidelines name several essentials. These are avoiding the allergen with dietary advice (ideally from a specialized dietitian) and a written treatment plan. They also cover education on recognizing symptoms and a prescription for medicines including an epinephrine auto-injector.E2Good¹⁷

Treatments that change the allergy itself, such as oral immunotherapy and omalizumab, have their own guide: Immunotherapy for allergies.

For clinicians

The 2025 EAACI management guideline suggests omalizumab for IgE-mediated food allergy in children from age 1 and in adults. It recommends oral immunotherapy for children and adolescents with peanut allergy, and suggests it for milk and egg allergy, generally after age 4.E2Good¹⁷

It suggests sublingual and epicutaneous immunotherapy for peanut allergy, noting that neither is yet available at the point of care.E2Good¹⁷

The evidence in this section (1 source)

Source	Design	Grade	Citations (NIH iCite)
17 Santos AF, Allergy, 2025	Guideline	E2Good	106 (RCR 35.47)

What is not known yet

The milk allergy study found the outlook was worse than earlier reports had suggested. Still, some patients outgrew it in their teens, which is why follow-up matters.E2Good⁵

For tree nuts, researchers could not firmly recommend test cut-offs for deciding when a supervised challenge makes sense.E2Good⁸

Questions you might bring to your clinician

Was this an IgE-mediated allergy, a non-IgE reaction, or something else such as an intolerance?
Which tests, if any, would help confirm it, and what can each test show and not show?
Is a supervised food challenge worth considering, now or later?
If this is a child's allergy, how often should it be checked again?
Is there a written emergency plan, and who should have a copy?

Every claim in this guide was written from its sources and checked against them word for word. Its clinical review by Dr. Recio, whose specialty is anesthesia, is pending; an allergist has not yet reviewed it. This line changes when each review is done.

Sources

Each source opens on PubMed, DailyMed or the publisher's page. Under each one are the exact words from it that this page relies on, copied word for word and checked against the original.

Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. NIAID-Sponsored Expert Panel, J Allergy Clin Immunol, 2010. E2Good GuidelinePMID 21134576; DOI 10.1016/j.jaci.2010.10.007; cited 1,036 times, relative citation ratio 34.84 (NIH iCite, 2026-10-16)
The words this page rests on
The Guidelines include a consensus definition for food allergy, discuss comorbid conditions often associated with food allergy, and focus on both IgE-mediated and non-IgE-mediated reactions to food.
Finally, because patients frequently confuse nonallergic food reactions, such as food intolerance, with food allergies, there is an unfounded belief among the public that food allergy prevalence is higher than it truly is.
Prevalence and Severity of Food Allergies Among US Adults. Gupta RS, JAMA Netw Open, 2019. E2Good Observational studyPMID 30646188; DOI 10.1001/jamanetworkopen.2018.5630; cited 769 times, relative citation ratio 42.2 (NIH iCite, 2026-10-16)
The words this page rests on
Estimated convincing food allergy prevalence among US adults was 10.8% (95% CI, 10.4%-11.1%), although 19.0% (95% CI, 18.5%-19.5%) of adults self-reported a food allergy.
These data suggest that at least 10.8% (>26 million) of US adults are food allergic, whereas nearly 19% of adults believe that they have a food allergy. Consequently, these findings suggest that it is crucial that adults with suspected food allergy receive appropriate confirmatory testing and counseling to ensure food is not unnecessarily avoided and quality of life is not unduly impaired.
The most common allergies were shellfish (2.9%; 95% CI, 2.7%-3.1%), milk (1.9%; 95% CI, 1.8%-2.1%), peanut (1.8%; 95% CI, 1.7%-1.9%), tree nut (1.2%; 95% CI, 1.1%-1.3%), and fin fish (0.9%; 95% CI, 0.8%-1.0%).
Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis. Storhaug CL, Lancet Gastroenterol Hepatol, 2017. E1Strong Meta-analysisPMID 28690131; DOI 10.1016/S2468-1253(17)30154-1; cited 249 times, relative citation ratio 12.22 (NIH iCite, 2026-10-16)
The words this page rests on
Lactose malabsorption is widespread in most of the world, with wide variation between different regions and an overall frequency of around two-thirds of the world's population. Acknowledging regional patterns of lactose malabsorption is important to guide management of gastrointestinal symptoms.
When standardising for country size, the global prevalence estimate of lactose malabsorption was 68% (95% CI 64-72), ranging from 28% (19-37) in western, southern, and northern Europe to 70% (57-83) in the Middle East.
Evidence that histamine is the causative toxin of scombroid-fish poisoning. Morrow JD, N Engl J Med, 1991. E2Good Observational studyPMID 1997836; DOI 10.1056/NEJM199103143241102; cited 163 times, relative citation ratio 7.06 (NIH iCite, 2026-10-16)
The words this page rests on
Scombroid-fish poisoning is associated with urinary excretion of histamine in quantities far exceeding those required to produce toxicity. The histamine is most likely derived from the spoiled fish. These results identify histamine as the toxin responsible for scombroid-fish poisoning.
The highest morbidity worldwide from fish poisoning results from the ingestion of spoiled scombroid fish, such as tuna and mackerel, and its cause is not clear. Histamine could be responsible, because spoiled scombroid fish contain large quantities of histamine.
Symptoms of scombrotoxism--flushing and headache--began 10 to 30 minutes after the ingestion of fish.
The natural history of IgE-mediated cow's milk allergy. Skripak JM, J Allergy Clin Immunol, 2007. E2Good Observational studyPMID 17935766; DOI 10.1016/j.jaci.2007.08.023; cited 538 times, relative citation ratio 16.11 (NIH iCite, 2026-10-16)
The words this page rests on
Rates of resolution were 19% by age 4 years, 42% by age 8 years, 64% by age 12 years, and 79% by 16 years.
The prognosis for CMA in this population is worse than previously reported. However, some patients developed tolerance during adolescence, indicating that follow-up and re-evaluation of CMA patients is important in their care. cm-IgE level is highly predictive of outcome.
The natural history of egg allergy. Savage JH, J Allergy Clin Immunol, 2007. E2Good Observational studyPMID 18073126; DOI 10.1016/j.jaci.2007.09.040; cited 383 times, relative citation ratio 11.06 (NIH iCite, 2026-10-16)
The words this page rests on
A majority of patients with egg allergy will develop egg tolerance, although the rate of tolerance development is slower than described previously.
Kaplan-Meier analysis predicted resolution in 4% of patients with egg allergy by age 4 years, 12% by age 6 years, 37% by age 10 years, and 68% by age 16 years.
Most patients with egg allergy are likely to develop egg tolerance by late childhood, with the exception of patients with an egg IgE greater than 50 kU/L, who are unlikely to develop egg tolerance.
The natural history of peanut allergy. Skolnick HS, J Allergy Clin Immunol, 2001. E2Good Observational studyPMID 11174206; DOI 10.1067/mai.2001.112129; cited 382 times, relative citation ratio 10.81 (NIH iCite, 2026-10-16)
The words this page rests on
This study demonstrates that peanut allergy is outgrown in about 21.5% of patients. Patients with low PN-IgE levels should be offered a peanut challenge in a medical setting to demonstrate whether they can now tolerate peanuts.
It has traditionally been assumed that peanut allergy is rarely outgrown.
Sixty-seven percent of patients with PN-IgE levels less than 2 kU(A)/L and 61% with levels less than 5 kU(A)/L had negative challenge results.
The natural history of tree nut allergy. Fleischer DM, J Allergy Clin Immunol, 2005. E2Good Observational studyPMID 16275381; DOI 10.1016/j.jaci.2005.09.002; cited 197 times, relative citation ratio 5.88 (NIH iCite, 2026-10-16)
The words this page rests on
Approximately 9% of patients outgrow TN allergy, including some who had prior severe reactions. Although ideal cutoffs for challenge cannot be firmly recommended on the basis of these data, patients aged 4 years or older with all TN-IgE levels of 5 kU(A)/L or less should be considered for challenge.
Nine of 20 patients who had previously reacted to a TN passed challenges, so that 9 (8.9%; 95% CI, 4% to 16%) of 101 patients with a history of prior TN reactions outgrew TN allergy.
Prevalence of adverse reactions to food in Germany - a population study. Zuberbier T, Allergy, 2004. E2Good Observational studyPMID 14982518; DOI 10.1046/j.1398-9995.2003.00403.x; cited 208 times, relative citation ratio 6.99 (NIH iCite, 2026-10-16)
The words this page rests on
The point prevalence of adverse reactions to food confirmed by DBPCFC tests in the Berlin population as a mean of all age groups was 3.6% (95% confidence interval [3.0-4.2%]) and 3.7% in the adult population (18-79 years, 95% confidence interval [3.1-4.4.%]). Two and a half percent were IgE-mediated and 1.1% non-IgE-mediated, females were more frequently affected (60.6%).
The self-reported lifetime prevalence of any adverse reaction to food in the Berlin population (mean age 41 years) was 34.9%.
The data also show that an individualized stepwise approach including provocation tests is mandatory to confirm the diagnosis.
Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel (full text). Boyce JA, 2010. E2Good Guideline
The words this page rests on
A food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.
Because individuals can develop allergic sensitization (as evidenced by the presence of allergen-specific IgE (sIgE)) to food allergens without having clinical symptoms on exposure to those foods, an sIgE-mediated FA requires both the presence of sensitization and the development of specific signs and symptoms on exposure to that food. Sensitization alone is not sufficient to define FA.
Coeliac disease. Lebwohl B, Lancet, 2018. Review Expert reviewPMID 28760445; DOI 10.1016/S0140-6736(17)31796-8; cited 738 times, relative citation ratio 38.21 (NIH iCite, 2026-10-16)
The words this page rests on
Coeliac disease occurs in about 1% of people in most populations.
Coeliac disease develops in genetically susceptible individuals who, in response to unknown environmental factors, develop an immune response that is subsequently triggered by the ingestion of gluten. The disease has many clinical manifestations, ranging from severe malabsorption to minimally symptomatic or non-symptomatic presentations.
Diagnosis requires the presence of duodenal villous atrophy, and most patients have circulating antibodies against tissue transglutaminase; in children, European guidelines allow a diagnosis without a duodenal biopsy provided that strict symptomatic and serological criteria are met.
The International Guideline for the Definition, Classification, Diagnosis and Management of Urticaria. Zuberbier T, Allergy, 2026. E2Good GuidelinePMID 41649409; DOI 10.1111/all.70210; cited 42 times, relative citation ratio 32.51 (NIH iCite, 2026-10-16)
The words this page rests on
Urticaria is a frequent, mast cell-driven disease, defined by a rapid appearance of wheals, angioedema, or both. The lifetime prevalence of acute urticaria is estimated to be approximately 20%.
Natural history of peanut allergy and predictors of resolution in the first 4 years of life: A population-based assessment. Peters RL, J Allergy Clin Immunol, 2015. E2Good Observational studyPMID 25725989; DOI 10.1016/j.jaci.2015.01.002; cited 170 times, relative citation ratio 7.13 (NIH iCite, 2026-10-16)
The words this page rests on
Peanut allergy resolved in 22% (95% CI, 14% to 31%) of children by age 4 years.
Thresholds for SPT and sIgE results at age 4 years with a 95% PPV for persistent peanut allergy are an SPT response of 8 mm or greater and an sIgE level of 2.1 kU/L or greater.
Tolerance to extensively heated milk in children with cow's milk allergy. Nowak-Wegrzyn A, J Allergy Clin Immunol, 2008. E2Good Observational studyPMID 18620743; DOI 10.1016/j.jaci.2008.05.043; cited 390 times, relative citation ratio 12.18 (NIH iCite, 2026-10-16)
The words this page rests on
The majority (75%) of children with milk allergy tolerate heated milk.
Sixty-eight subjects tolerated extensively heated milk only, 23 reacted to heated milk, and 9 tolerated both heated and unheated milk.
Immunologic changes in children with egg allergy ingesting extensively heated egg. Lemon-Mulé H, J Allergy Clin Immunol, 2008. E2Good Observational studyPMID 18851876; DOI 10.1016/j.jaci.2008.09.007; cited 331 times, relative citation ratio 10.63 (NIH iCite, 2026-10-16)
The words this page rests on
The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.
Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg.
EAACI guidelines on the diagnosis of IgE-mediated food allergy. Santos AF, Allergy, 2023. E2Good GuidelinePMID 37815205; DOI 10.1111/all.15902; cited 265 times, relative citation ratio 42.15 (NIH iCite, 2026-10-16)
The words this page rests on
Reassessment of food allergic children with allergy tests and/or OFCs periodically over time will enable reintroduction of food into the diet in the case of spontaneous acquisition of oral tolerance.
EAACI guidelines on the management of IgE-mediated food allergy. Santos AF, Allergy, 2025. E2Good GuidelinePMID 39473345; DOI 10.1111/all.16345; cited 106 times, relative citation ratio 35.47 (NIH iCite, 2026-10-16)
The words this page rests on
Following the confirmation of IgE-mediated food allergy diagnosis, allergen avoidance and dietary advice (with support of a specialised dietitian, if possible) together with the provision of a written treatment plan, education on the recognition of allergic symptoms and prescription of medication including adrenaline using an auto-injector are essential.
As immunomodulatory interventions, omalizumab is suggested for treatment of IgE-mediated food allergy in children from the age of 1 and adults; and oral allergen-specific immunotherapy is recommended for children and adolescents with peanut allergy and suggested for milk and egg allergies (generally after 4 years of age for milk and egg).
Sublingual and epicutaneous immunotherapy are suggested for peanut allergy but are not yet available at the point of care.

NextReading food labels RelatedAllergy tests, and why IgG panels do not diagnose allergy Before the visitPrint the allergist visit checklist

A food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.

The diagnosis of non-IgE-mediated FA is based on signs and symptoms occurring reproducibly on exposure to food, resolution of those signs and symptoms with specific food avoidance, and, most often, histologic evidence of an immunologically mediated process, such as eosinophilic inflammation of the GI tract.

The terms allergy and allergic disease are broadly encompassing and include clinical conditions associated with altered immunologic reactivity that may be either IgE mediated or non-IgE mediated. IgE is a unique class of immunoglobulin that mediates an immediate allergic reaction.

A problem often confused with food allergy is food intolerance, which is also an abnormal response to a food product, but differs from an allergy. A common example is an intolerance to lactose, a sugar found in many milk products that can cause an uncomfortable buildup of gas in the gastrointestinal tract.

The gold standard for diagnosing food allergy is an oral food challenge. In this procedure, a food is eaten slowly, in gradually increasing amounts, under medical supervision to accurately diagnose or rule out a true food allergy.

Food sensitization means a person has a positive IgE test to a food but can still tolerate that food in their diet.

Histamine is a chemical released by mast cells in the immune system when the body encounters an allergen. This causes an allergic reaction.

Urticaria is a frequent, mast cell-driven disease, defined by a rapid appearance of wheals, angioedema, or both. The lifetime prevalence of acute urticaria is estimated to be approximately 20%.

The ability to tolerate baked milk or egg, such as in a cake or muffin, has been associated with an increased chance of tolerance development. Studies report that about 70% of CM- and egg-allergic children can tolerate baked milk or egg and that incorporating baked milk or egg into the diet is well tolerated.

Individuals may tolerate food only for a short term, perhaps because they have been desensitized by exposure to the food. Alternatively, they may develop long-term tolerance. The specific term tolerance is used in these Guidelines to mean that an individual is symptom free after consumption of the food or upon oral food challenge weeks, months, or even years after the cessation of treatment.

In a skin-prick test, a lancet is used to prick the skin under a drop of allergen extract. If a person is allergic to the allergen, a raised red bump will appear at the site of the prick after about 15 minutes.

A specific IgE test measures how much IgE your body makes in response to a single allergen. A separate test is done for each allergen that may be causing your allergies.

Epinephrine, a medicine to treat anaphylaxis. Your provider may give you a prescription for an epinephrine auto-injector. It is a device used to inject epinephrine when someone is having symptoms of anaphylaxis.

Epinephrine is a medicine administered as an injection or in the form of a nasal spray that is used to treat life-threatening allergic reactions called anaphylaxis (an-a-fi-LAK-sis). These very serious reactions are most commonly caused by foods, drugs and stinging insects.

An allergen is a usually harmless substance capable of triggering a response that starts in the immune system and results in an allergic reaction.

Oral immunotherapy involves eating small doses of a food that causes an allergy and gradually increasing the size of those doses.

The first approach, called immunotherapy, involves exposing a person to a food allergen in a controlled way to reduce their immune response to the allergen.

In epicutaneous immunotherapy, a wearable patch delivers an allergen to the skin’s surface.