7 Uncommon Food Allergies That Could Be Causing Your Symptoms

Bowl of sliced banana, orange, and apple

Verywell / Zorica Lakonic

You hear a lot about the most common food allergies, which include milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans. However, it is also possible to have a food allergy to foods you might not expect, such as citrus and celery.

In many cases, these reactions are caused by a condition that's known as oral allergy syndrome (OAS) or pollen-food allergy syndrome (PFAS).

Food Allergies and Cross-Reactivity

People who have oral allergy syndrome generally already have been diagnosed with allergies to inhaled allergens such as tree, weed, or grass pollen.

Some foods contain proteins that are similar in structure to these inhaled allergens, and people with OAS also can react with food allergy symptoms when they consume those foods because of those similar proteins. This is a process known as cross-reactivity.

In other words, people with OAS have an allergy to inhaled pollens, and because of that allergy, they may also exhibit food allergy symptoms to certain foods that come from plants that are closely related.

Cross-reactivity has been documented between birch pollen, mugwort pollen, grass pollens, ragweed and Timothy grass with a variety of fruits, legumes, grains, nuts, seeds, vegetables, herbs, and spices.

The patterns and prevalence of cross-reactivity vary across the world, due to geographical and climatic differences.

Foods Related to Oral Allergy Syndrome

Here are some of the most common food triggers of OAS:


About 50% to 75% of people with an allergy to birch pollen and mugwort pollen also react to raw apple due to oral allergy syndrome.

Symptoms of apple allergy primarily reside within the mouth and can occur within five minutes of eating the offending food in those who are the most sensitive. Nearly all individuals will experience symptoms within 30 minutes of eating.

Symptoms tend to resolve once the individual stops eating the apple. Severe reactions are possible, particularly if throat swelling is involved, since this can cause breathing difficulty.


An allergy to citrus fruits may include one or more of the following types: orange, grapefruit, lemon, and lime. Reactions can range from an itchy mouth to full-fledged anaphylaxis.

There is cross-reactivity between citrus fruits, suggesting the allergy to one citrus fruit increases the likelihood of allergy to another. Grass pollens, Timothy grass, birch pollen, and mugwort pollen may cross-react with citrus fruit due to their similar protein make-up.


Allergic reactions to banana vary widely and may include itching of the mouth and throat, hives (urticaria), swelling (angioedema), and wheezing.

Symptoms are most closely related to oral allergy syndrome, with localized symptoms in the mouth. In most cases, symptoms begin within minutes of eating the fruit.

Cross-reactivity between ragweed and banana is known to play a role.

If you have a banana allergy, you also may react to natural rubber latex. Latex is produced from the sap of the rubber tree, which contains similar proteins to those in bananas and other related foods, such as kiwi and avocado.


Coriander is in the family of spices that includes caraway, fennel, and celery—all of which have been associated with allergic reactions. Cinnamon, saffron, and mustard also have been noted for causing reactions.

Across the globe, spices have become some of the most common food allergens. It appears that cross-reactivity to birch pollen, mugwort pollen, grass pollens, and Timothy grass are the most common culprits. The main symptom is itching in the mouth.

Some spices, including oregano, thyme, coriander, caraway seed, cumin, and cayenne pepper, have been associated with an anaphylactic reaction, though this is extremely rare.


A celery allergy is relatively common, making celery a top allergen. Cross-reactivity to birch pollen and mugwort pollen, as well as grass pollens and Timothy grass have been identified. According to some research, 30% to 40% of allergic individuals are sensitized to celery.

The most common symptoms of a celery allergy include itching and swelling in and around the mouth. Occasionally, there can be a systemic response, sometimes leading to anaphylaxis.


Coconut allergy is very rare. According to the FDA, coconut is classified as a tree nut for the purposes of ingredient labeling and consumer protection. Coconut is not a tree nut, however, and most individuals with tree nut allergy can eat coconut without any issues. While few individuals will have a coconut allergy, they do exist. Symptoms include an itchy mouth and, extremely rarely, anaphylaxis. Products such as lotions and soaps containing coconut may cause contact dermatitis in some people.


Meat allergy is uncommon but some individuals have an allergy to meat, such as beef, lamb, pork, and goat. A red meat allergy, also known as Alpha gal syndrome (AGS), is a distinct allergy condition that is not related to OAS or PFAS. A red meat allergy to beef and pork is associated with a tick bite from the Lone Star tick. This tick can be found from Texas across the Southeast and up to New England.

Reactions to red meat are often delayed, occurring many hours after eating it, although this isn’t always the case.

Symptoms can be severe and anaphylactic reactions with dizziness or lightheadedness, flushing, difficulty breathing can occur. Common symptoms include nausea, vomiting, and diarrhea with most common being hives, rash and itchy skin. If you develop an allergy to one type of meat, you may develop an allergy to another, such as poultry. A very small number of children who are allergic to milk may also be allergic to meat.

The delay between eating red meat and symptoms makes diagnosing red meat allergy challenging. However, individuals with a true red meat allergy will test positive following an immunoglobulin E skin prick test. A blood test can confirm positive alpha-gal antibodies in bloodstream. This is a key test for diagnosis of alpha-gal syndrome.


When individuals who are allergic to latex consume a food containing a similar antigen (a protein responsible for an allergic reaction), symptoms develop. This is called latex-fruit syndrome.

Not all people who are allergic to latex will have this condition. Between 30% and 50% of individuals with a natural rubber latex allergy are sensitized to other foods, especially fruit.

It's most common to see cross-reactivity with avocado, banana, cassava, chestnut, kiwi, mango, papaya, passion fruit, tomato, turnip, zucchini, bell pepper, celery, potato, and custard apple. However, sensitivity to various other foods has been recorded.

If a latex-allergic person has had a reaction to a food, they should avoid that food. If there is doubt, an oral challenge test of the food should be performed under the supervision of a healthcare provider.

Frequently Asked Questions

How is oral allergy syndrome diagnosed?

Several tests may be used to diagnose OAS, including a skin prick test, a blood test, and an oral food challenge.

Is oral allergy syndrome treatable?

Yes. The most effective way to treat a food allergy, including OAS, is by avoiding the trigger. Always read the ingredient list on foods that might contain the offending substance, and ask restaurant staff about it before ordering.

Will cooking foods remove allergens?

Yes. High temperatures break down the proteins responsible for OAS. Other strategies are to eat the food in canned form or to peel foods that can be peeled, as the proteins responsible for allergies are often concentrated in the skin.

Can a food allergy suddenly occur?

Yes. In fact, research has shown that food allergies are on the rise in both adults and children and that oral allergy syndrome is the most common form of adult-onset food allergy. People may develop allergies to foods they could previously eat without symptoms.

What foods can I safely consume if I have oral allergy syndrome?

Unless you have known allergies to other foods, you should be able to consume anything other than the foods that cause an allergic reaction. With OAS, the important thing is to avoid those foods which cause symptoms.

A Word From Verywell

If you have a respiratory allergy to common pollens, such as birch, mugwort, grass, or ragweed, you should be aware of the possibility of oral allergy syndrome.

Talk to your healthcare provider if you've ever experienced symptoms after eating one of these potentially cross-reactive foods. If you experience a severe reaction, such as throat swelling or difficulty breathing, seek emergency medical care.

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19 Sources
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  1. American Academy of Asthma, Allergy & Immunology. Oral allergy syndrome (OAS).

  2. American College of Allergy, Asthma & Immunology. Pollen food allergy syndrome.

  3. Sussman G, Sussman A, Sussman D. Oral allergy syndromeCan Med Assoc J. 2010;182(11):1210-1211. doi:10.1503/cmaj.090314

  4. Iorio R, Del Duca S, Calamelli E et al. Citrus allergy from pollen to clinical symptomsPLoS ONE. 2013;8(1):e53680. doi:10.1371/journal.pone.0053680

  5. Anaphylaxis Campaign. Banana.

  6. American College of Allergy, Asthma & Immunology. Latex allergy.

  7. Aronson J. Index of Drug Names. In: Aronson J, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham MA: Elsevier; 2016:651.

  8. Popescu F. Cross-reactivity between aeroallergens and food allergensWorld J Methodol. 2015;5(2):31. doi:10.5662/wjm.v5.i2.31

  9. American Academy of Allergy Asthma & Immunology. Can spices cause allergic reactions?

  10. The University of Manchester. Celery.

  11. Treudler R, Simon JC. Pollen-related food allergy: an updateAllergo J Int 26, 273–282 (2017). doi:10.1007/s40629-017-0022-2

  12. Anagnostou K. Coconut allergy revisitedChildren. 2017;4(10):85. doi:10.3390/children4100085

  13. American Academy of Asthma Allergy & Immunology. Coconut contact urticaria and specific IGE.

  14. American College of Allergy, Asthma & Immunology. Meat allergy.

  15. Doenhoff M, El-Faham M, Liddell S, et al. Cross-reactivity between schistosoma mansoni antigens and the latex allergen hev b 7: Putative implication of cross-reactive carbohydrate determinants (CCDs)PLoS ONE. 2016;11(7):e0159542. doi:10.1371/journal.pone.0159542

  16. Calamelli E, Piccinno V, Giannetti A, Ricci G, Pession A. Latex-fruit syndrome and degree of severity of natural rubber latex allergy: Is there a linkClin Transl Allergy. 2011;1(S1). doi:10.1186/2045-7022-1-s1-o18

  17. Hussein H, Mensah RK, Brown RS. Diagnosis and management of oral allergy syndrome, the itchy tongue allergic reaction. Compend Contin Educ Dent. 2019;40(8):502-506.

  18. American College of Asthma, Allergy & Immunology. Anaphylaxis.

  19. Kivity S. Adult-onset food allergy. Isr Med Assoc J. 2012 Jan;14(1):70-2. PMID: 22624448

Additional Reading
  • Joneja JV. The Health Professional’s Guide to Food Allergies and Intolerances.