Causes of Citrus Allergy and Foods to Avoid

Table of ContentsView AllTable of ContentsCauses and TypesSymptomsDiagnosisTreatment

Table of ContentsView All

View All

Table of Contents

Causes and Types

Symptoms

Diagnosis

Treatment

More often, however, you might experienceoral allergy syndrome (OAS)in which your immune system mistakes proteins in citrus for those in foods you are truly allergic to, causing mild, short-term symptoms like tingling and itching of the lips, tongue, and throat.Contact with essential oils from the rind of the fruit can also cause an allergic reaction known ascontact dermatitis.

Causes of a Citrus Allergy

Allergens are proteins that serve as the “ID tag” for a specific substance. If you have a citrus allergy, your immune system is reacting to a specific protein in the fruit.

The release of IgE sets off a chain reaction, flooding the body withhistamineand other inflammatory chemicals that lead toallergy symptoms.

Scientists have identified five allergens that can induce a citrus allergy, known as:

Cit s 1, cit s 2, cit s3, and cit s IFR are all found in varying degrees in the peel and pulp of the fruit.Citrin is mainly found in citrus seeds and pectin.

True Allergy vs. Cross-Reactivity

Citrus allergies are known to be rare. True citrus allergies may even be rarer given that many are thought to be due to allergic cross-reactivity.

Cross-reactivity occurs when the immune system regards the proteins of one substance (such as pollen) and those of another substance (such as a fruit) as being similar. In such cases, the body will react as if they are the same, triggering the release of IgE whether the person is truly allergic or not.

Cross-reactivity is especially high with cit s 2 (profiling). Studies have shown that as many as 30% of people withpollen allergiesare cross-reactive with profilin, particularly those with allergies to:

In such cases, a person may experienceoral allergy syndrome (OAS), a relatively mild and short-lived reaction mainly limited to the mouth and lips. Profilin cross-reactivity is also common with tree nuts, melons, watermelons, tomatoes, pineapple, peaches, and bananas.

With citrin, cross-reactivity is most common with cashews or pistachios.

Allergic Contact Dermatitis

Allergic contact dermatitis (ACD)is a form ofeczemain which physical contact with an allergen provokes a skin reaction, leading to redness, rash, and itching within hours or days.

Unlike a true allergy or allergic cross-reactivity, ACD doesnotinvolve IgE. Instead, the allergens bind directly to immune cells in the skin, calledmast cells, causing them to break open and release histamine into surrounding tissues.

The reaction is often delayed, usually only manifesting with symptoms after two or more days.

Allergic Reaction or Food Sensitivity?Sensitivity or intolerancetocitric acidfound in citrus fruits can also cause allergy-like symptoms.In such cases, the body will respond with gastrointestinal symptoms like bloating, abdominal pain, or heartburn within a half hour of eating the fruit. Hives can also occur.Reactions like these are not considered an allergy because they do not involve IgE. Citric acid has neither been identified as an allergen nor a cause of citrus allergies.

Allergic Reaction or Food Sensitivity?

Sensitivity or intolerancetocitric acidfound in citrus fruits can also cause allergy-like symptoms.In such cases, the body will respond with gastrointestinal symptoms like bloating, abdominal pain, or heartburn within a half hour of eating the fruit. Hives can also occur.Reactions like these are not considered an allergy because they do not involve IgE. Citric acid has neither been identified as an allergen nor a cause of citrus allergies.

Sensitivity or intolerancetocitric acidfound in citrus fruits can also cause allergy-like symptoms.In such cases, the body will respond with gastrointestinal symptoms like bloating, abdominal pain, or heartburn within a half hour of eating the fruit. Hives can also occur.

Reactions like these are not considered an allergy because they do not involve IgE. Citric acid has neither been identified as an allergen nor a cause of citrus allergies.

Citrus Allergy Symptoms

The symptoms of a citrus allergy can vary based on which type of allergy you are experiencing.

Truefood allergiesusually cause symptoms within several minutes to two hours of eating a food. Multiple organ systems can be affected, causing:

Oral allergy syndrome (OAS)causes relatively mild symptoms within minutes of eating a cross-reactive food, Symptoms can last for minutes or hours and may include:

Allergic contact dermatitis (ACD)can cause localized symptoms within 48 to 72 hours that may persist for a week or more. These include:

Risk of AnaphylaxisWhile rare, citrus may cause a potentially life-threatening allergy known asanaphylaxis. Studies suggest that Asian people and people allergic to cit s 3 may be at greater risk.Call 911 if you experience the following signs or symptoms after eating citrus:A sudden, severe outbreak of rashShortness of breath or wheezingSwelling of the face, neck, or throatLightheadedness or faintingRapid or irregular heartbeatsA cold sweatA feeling of impending doomIf left untreated, anaphylaxis can lead to shock, coma, respiratory failure, and death.

Risk of Anaphylaxis

While rare, citrus may cause a potentially life-threatening allergy known asanaphylaxis. Studies suggest that Asian people and people allergic to cit s 3 may be at greater risk.Call 911 if you experience the following signs or symptoms after eating citrus:A sudden, severe outbreak of rashShortness of breath or wheezingSwelling of the face, neck, or throatLightheadedness or faintingRapid or irregular heartbeatsA cold sweatA feeling of impending doomIf left untreated, anaphylaxis can lead to shock, coma, respiratory failure, and death.

While rare, citrus may cause a potentially life-threatening allergy known asanaphylaxis. Studies suggest that Asian people and people allergic to cit s 3 may be at greater risk.

Call 911 if you experience the following signs or symptoms after eating citrus:

If left untreated, anaphylaxis can lead to shock, coma, respiratory failure, and death.

Differentiating a true allergy from cross-reactivity can be difficult because both involve IgE (as opposed to ACD which does not). In such cases, more complicated (and costly) tests can be ordered to make the determination.

The best way to treat citrus allergy is to avoid citrus fruits. You will also need to avoid products that contain citrus, particularly if you have ACD.

If your allergy is mild, you can try takingantihistamines. This may help reduce symptoms like itching in the mouth. If you have a skin allergy,topical hydrocortisonemay help.

People at risk of anaphylaxis should carry anEpiPen. This prefilled auto-injector contains a dose ofepinephrine(adrenaline) which helps counter the effects of anaphylaxis and preventsshock. It is important to keep your EpiPen with you at all times in case of a severe reaction.

With allergy shots, initial treatment can last from four to six months with follow-up injections thereafter.

Summary

13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.ThermoFisher Scientific.f33 Orange.Mahdani FY, Parmadiati AE, Ernawait DS.Citrus limonpeel essential oil–induced type IV hypersensitivity reaction.J Exp Pharmacol. 2020 Jul 27;12:213–220. doi:10.2147/JEP.S256139American College of Allergy, Asthma, and Immunology.Allergies 101.Gilje E, Bauer M.Citrin allergy is rare but perplexing.Ann Allergy Asthma Immunol. 2023 Dec;131(6):685-686. doi:10.1016/j.anai.2023.09.007Kazatskhy AM, Wood RA.Classification of food allergens and cross-reactivity.Curr Allergy Asthma Rep.2016 Mar;16(3):22. doi:10.1007/s11882-016-0601-1Novak-Bilić G, Vučić M, Japundžić I, Meštrović-Štefekov J, Stanić-Duktaj S, Lugović-Mihić L.Irritant and allergic contact dermatitis - skin lesion characteristics.Acta Clin Croat. 2018 Dec;57(4):713-720. doi:10.20471/acc.2018.57.04.13American Academy of Allergy, Asthma, and Immunology.Citric acid and citrus allergy.American Academy of Allergy, Asthma and Immunology.Food intolerance versus food allergy.Johns Hopkins Medicine.Food allergies.Muluk NB, Cingi C.Oral allergy syndrome.Am J Rhinol Allergy. 2018;32(1):27-30. doi:10.2500/ajra.2018.32.4489Bilò MB, Martini M, Tontini C, Corsi A, Antonicelli L.Anaphylaxis.Eur Ann Allergy Clin Immunol. 2021;53(1):4-17. doi:10.23822/EurAnnACI.1764-1489.158American College of Allergy, Asthma, and Immunology.Allergy testing.American College of Allergy, Asthma, and Immunology.Allergy immunotherapy.

13 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.ThermoFisher Scientific.f33 Orange.Mahdani FY, Parmadiati AE, Ernawait DS.Citrus limonpeel essential oil–induced type IV hypersensitivity reaction.J Exp Pharmacol. 2020 Jul 27;12:213–220. doi:10.2147/JEP.S256139American College of Allergy, Asthma, and Immunology.Allergies 101.Gilje E, Bauer M.Citrin allergy is rare but perplexing.Ann Allergy Asthma Immunol. 2023 Dec;131(6):685-686. doi:10.1016/j.anai.2023.09.007Kazatskhy AM, Wood RA.Classification of food allergens and cross-reactivity.Curr Allergy Asthma Rep.2016 Mar;16(3):22. doi:10.1007/s11882-016-0601-1Novak-Bilić G, Vučić M, Japundžić I, Meštrović-Štefekov J, Stanić-Duktaj S, Lugović-Mihić L.Irritant and allergic contact dermatitis - skin lesion characteristics.Acta Clin Croat. 2018 Dec;57(4):713-720. doi:10.20471/acc.2018.57.04.13American Academy of Allergy, Asthma, and Immunology.Citric acid and citrus allergy.American Academy of Allergy, Asthma and Immunology.Food intolerance versus food allergy.Johns Hopkins Medicine.Food allergies.Muluk NB, Cingi C.Oral allergy syndrome.Am J Rhinol Allergy. 2018;32(1):27-30. doi:10.2500/ajra.2018.32.4489Bilò MB, Martini M, Tontini C, Corsi A, Antonicelli L.Anaphylaxis.Eur Ann Allergy Clin Immunol. 2021;53(1):4-17. doi:10.23822/EurAnnACI.1764-1489.158American College of Allergy, Asthma, and Immunology.Allergy testing.American College of Allergy, Asthma, and Immunology.Allergy immunotherapy.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

ThermoFisher Scientific.f33 Orange.Mahdani FY, Parmadiati AE, Ernawait DS.Citrus limonpeel essential oil–induced type IV hypersensitivity reaction.J Exp Pharmacol. 2020 Jul 27;12:213–220. doi:10.2147/JEP.S256139American College of Allergy, Asthma, and Immunology.Allergies 101.Gilje E, Bauer M.Citrin allergy is rare but perplexing.Ann Allergy Asthma Immunol. 2023 Dec;131(6):685-686. doi:10.1016/j.anai.2023.09.007Kazatskhy AM, Wood RA.Classification of food allergens and cross-reactivity.Curr Allergy Asthma Rep.2016 Mar;16(3):22. doi:10.1007/s11882-016-0601-1Novak-Bilić G, Vučić M, Japundžić I, Meštrović-Štefekov J, Stanić-Duktaj S, Lugović-Mihić L.Irritant and allergic contact dermatitis - skin lesion characteristics.Acta Clin Croat. 2018 Dec;57(4):713-720. doi:10.20471/acc.2018.57.04.13American Academy of Allergy, Asthma, and Immunology.Citric acid and citrus allergy.American Academy of Allergy, Asthma and Immunology.Food intolerance versus food allergy.Johns Hopkins Medicine.Food allergies.Muluk NB, Cingi C.Oral allergy syndrome.Am J Rhinol Allergy. 2018;32(1):27-30. doi:10.2500/ajra.2018.32.4489Bilò MB, Martini M, Tontini C, Corsi A, Antonicelli L.Anaphylaxis.Eur Ann Allergy Clin Immunol. 2021;53(1):4-17. doi:10.23822/EurAnnACI.1764-1489.158American College of Allergy, Asthma, and Immunology.Allergy testing.American College of Allergy, Asthma, and Immunology.Allergy immunotherapy.

ThermoFisher Scientific.f33 Orange.

Mahdani FY, Parmadiati AE, Ernawait DS.Citrus limonpeel essential oil–induced type IV hypersensitivity reaction.J Exp Pharmacol. 2020 Jul 27;12:213–220. doi:10.2147/JEP.S256139

American College of Allergy, Asthma, and Immunology.Allergies 101.

Gilje E, Bauer M.Citrin allergy is rare but perplexing.Ann Allergy Asthma Immunol. 2023 Dec;131(6):685-686. doi:10.1016/j.anai.2023.09.007

Kazatskhy AM, Wood RA.Classification of food allergens and cross-reactivity.Curr Allergy Asthma Rep.2016 Mar;16(3):22. doi:10.1007/s11882-016-0601-1

Novak-Bilić G, Vučić M, Japundžić I, Meštrović-Štefekov J, Stanić-Duktaj S, Lugović-Mihić L.Irritant and allergic contact dermatitis - skin lesion characteristics.Acta Clin Croat. 2018 Dec;57(4):713-720. doi:10.20471/acc.2018.57.04.13

American Academy of Allergy, Asthma, and Immunology.Citric acid and citrus allergy.

American Academy of Allergy, Asthma and Immunology.Food intolerance versus food allergy.

Johns Hopkins Medicine.Food allergies.

Muluk NB, Cingi C.Oral allergy syndrome.Am J Rhinol Allergy. 2018;32(1):27-30. doi:10.2500/ajra.2018.32.4489

Bilò MB, Martini M, Tontini C, Corsi A, Antonicelli L.Anaphylaxis.Eur Ann Allergy Clin Immunol. 2021;53(1):4-17. doi:10.23822/EurAnnACI.1764-1489.158

American College of Allergy, Asthma, and Immunology.Allergy testing.

American College of Allergy, Asthma, and Immunology.Allergy immunotherapy.

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