Rare but Real Food Allergies

Citrus allergy is a rare but real food allergy. lacaosa/Getty Images

You hear a lot about the most common food allergies, however, in addition to the top eight, many other foods may cause an allergic reaction. In fact, according to the Centers for Disease Control and Prevention (CDC), more than 160 foods have caused food allergy reactions, demonstrating that many people react to foods that are outside the realm of the usual food allergens.


Oral allergy syndrome (OAS) or pollen-food allergy syndrome, is a condition where reactions in the mouth and throat occur from direct contact with food in a sensitized person who also has a respiratory allergy to inhaled allergens such as tree, weed, or grass pollens.

This sensitivity to both inhaled pollen and food is related to the similarity of allergen-containing proteins within both elements, called cross-reactivity. In other words, people with OAS have an allergy to inhaled plant materials that are related to the protein in the food that causes their oral symptoms.

Cross-reactivity has been documented between birch pollen, mugwort pollen, grass pollens, ragweed and Timothy grass with a variety of fruits, legumes and grains, nuts and seeds, and vegetable, herbs, and spices. The patterns and prevalence of cross-reactivity vary across the world, due to geographical and climatic differences.

Let's take a look at some of the most common foods related to OAS:

Apple Allergy

Apple allergy is correlated with OAS, with about 50 to 80 % of people with an allergy to birch pollen and mugwort pollen reacting to raw apple.

Symptoms of apple allergy primarily reside within the mouth and occur within 5 minutes of eating the offending food in most sensitive people. 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.

Citrus Allergy

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

Banana Allergy

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 the 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.

If you have a banana allergy you could also 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 foods such as kiwi and avocado.

Spice Allergy

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.

Celery Allergy

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

Coconut Allergy

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 issue. While few individuals will have a coconut allergy, they do exist. This article provides a more in-depth review of coconut allergy.

Meat Allergy

Meat allergy is uncommon but some individuals have an allergy to meat, beef, lamb, pork, and goat. A red meat allergy to beef and pork is associated with a tick bite from the Lone Star tick. This tick can be found in the Southeast, from Texas up to New England.

Reactions to red meat are often delayed, occurring many hours after eating red meat, although this isn’t always the case. Common symptoms include nausea, vomiting, and diarrhea, with the most common being itching. An anaphylactic reaction may occur in individuals who exercise after ingesting red meat.

If you develop an allergy to one type of meat, you may develop an allergy to another type of meat, 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.

Latex Allergy

When individuals who are allergic to latex consume a food containing a similar antigen (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. Up to 50 to 70% 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, he or she should avoid that food. If there is doubt, an oral challenge test of the food should be performed under the supervision of a doctor.

View Article Sources
  • Sources:
  • American College of Allergy, Asthma, and Immunology: http://acaai.org/allergies/types/food-allergies/types-food-allergy/meat-allergy
  • American College of Allergy, Asthma, and Immunology: http://acaai.org/allergies/types/food-allergies/types-food-allergy/oral-allergy-syndrome
  • Anaphylaxis Campaign: http://www.anaphylaxis.org.uk/what-is-anaphylaxis/knowledgebase/oral-allergy-syndromes-factsheet?page=8
  • Joneja JV. The Health Professional’s Guide to Food Allergies and Intolerances.