Oranges are in the Rutaceae family of plants. Other plants in this family include grapefruit, lemon, lime, kumquat and sichuan pepper.

There are 4 allergens found in oranges.

Cit s 1 is a germin like protein (GLP). These proteins have a role in guarding against stress and pathogens in the plant.

Cit s 2 is a profilin protein. Allergenic profilins are found exclusively in flowering plants and are minor pollen allergens.

Cit s 3 is a Lipid Transfer Protein (LTP). These proteins are resistant to heat and are found in many types of plants. Patients suffering from a more severe allergy to cooked fruit may be sensitised to this group of proteins.

Cit s 7 is a gibberellin regulated protein. Gibberellins are plant hormones associated with growth and development.

A 2023 study has shown oranges contain thaumatin like proteins. These are proteins which give foods their sweet flavour. They are 'heat labile' proteins, which means they can cause allergic reactions after heating, cooking and processing.

Like other citrus fruits oranges contain furanocoumarins. These chemicals can get on the skin and in combination with ultraviolet light (sunlight) can cause a sunburn like rash. Furanocoumarins are found in higher concentrations in fresh herbs and are natural irritants which can cause allergic contact dermatitis. This is more common in occupations where you are frequently coming into contact with the food, like chefs, cooks, growers and pickers.

Oranges are a low FODMAP food. FODMAP stands for Fermentable oligosaccharides, disaccharides, monosaccharides and polyols. Foods high in FODMAPs can cause symptoms of food intolerance, affecting the gastro intestinal system and this can be mistaken for a true IgE food allergy.

Oranges are not high in histamine, but contain putrescine, which is another biogenic amine found in citrus fruits, chocolate, tea and nuts. Putrescine can have have similar effects on people who suffer with histamine intolerance. They have been flagged as amber here as it would depend on how sensitive you are as to how well you might tolerate them.

Oranges are a food high in salicylates. Salicylates have the potential to cause worsening of asthma, swelling, itching and hives as well as food intolerance symptoms in people who are sensitive to salicylates.

You can read more about Food Intolerances on the dedicated Food Intolerance Page.

You may be suffering from LTP Syndrome if you have reactions to various fruits, vegetables and nuts and your reactions continue to be severe after you have discarded the peel and have cooked the food.

Allergy to orange is sometimes linked to Celery-Mugwort-Spice Syndrome as the sensitising allergen is a profilin protein called Art v 4, these proteins are also sometimes also called Bet v 2 proteins.

There is also a link between orange and Latex Food Syndrome. The plant involved in latex allergy Hevea brasiliensis, the rubber tree plant, has an allergen called Hev b 8 which is a profilin protein. Those very sensitised to latex may have a contact allergic reaction from other foods or plants containing profilin proteins, there is less evidence of this than sensitisation to other latex linked proteins like hevein and chitinases.

Common foods involved in LTP allergy include kiwi, strawberries, sunflower seeds, walnut, apple, mulberry, banana, pea, apricot, cherry, plum, almond, peach pomegranate, raspberry, tomato, grape, celery, peanut, asparagus, cabbage, broccoli, chestnut, lemon, tangerine, orange, hazelnut, lettuce, lentils, lupin, green bean, pear, mustard, wheat and maize.

Other foods containing profilin allergens are celery, peanut, soyabeans, lychee, walnut, lupin, almonds, mustard, hazelnut, kiwi, pineapple, chilli, melon, strawberry, apple, banana, aubergine (eggplant), peach, pear, tomato, dates, cherry, carrot, barley and wheat. Allergic reactions to some of these foods may be considered a marker of profilin hypersensitivity.

Gibberellin regulated proteins are also found in chilli, cherry, apricots, peach and pomegranate.

Thaumatin proteins are found in apple, banana, cherry, pepper, garlic, grape, kiwi and peach.

Please note that these food lists are not exhaustive, the most up to date information can be found on the Cross Reactivity Tool.

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