Orange is a food which may result in allergy symptoms in sensitised individuals.

Orange Allergy Test: Allergen Exposure

Oranges are the most widely grown and consumed of the citrus fruits, having been cultivated over 3,000 years ago in China and since spreading to warm-climate areas, including Portugal, Spain, Israel, North Africa and the south of the United States. Principal exporters are Spain and Israel, while the United States leads the world in total annual production.

The many varieties (Mandarin, tangerine, blood orange, etc.) fall under the basic categories of loose-skinned and tight-skinned, and sweet and bitter (the latter not eaten raw or on its own, but used as a flavouring in processed foods).

The fruit is often eaten fresh and raw. The juice is also extracted and sold fresh and as frozen concentrate, or employed as flavouring in jellies, ice cream, etc. The rind serves as flavouring in cakes, marmalade and other sweets. The flowers are cooked as a vegetable or made into a tea.

Oranges are high in vitamin C and flavonoids. They contain thiamin, folate and pectin, which may lower blood cholesterol levels. The fruit, juice and rind are folk remedies for many ailments.

An essential oil from the peel is used as a food flavouring and also in perfumery and medicines. One of the plant’s more recent applications is as a source of antioxidants and chemical exfoliants in specialised cosmetics.

Orange Allergy Test: Allergen Description

A number of proteins of various sizes have been isolated, and a number characterised, including major allergens.

An early study suggested that the major allergenic components of orange reside in orange seeds instead of orange juice/pulp, and that orange seed contains highly potent allergens, which may induce symptoms after careless chewing.

Orange Allergy Test: Potential Cross-Reactivity

Extensive cross-reactivity between the different individual species of the genus could be expected.

The presence of a profilin in orange, Cit s 2, may result in cross-reactivity with other foods containing profilin, and the profilin is a common cause of OAS. Rosaceae foods, tree nuts, melon and watermelon, tomato, pineapple, citrus fruit and banana are the more frequently offending foods.

Orange and lemon lipid transfer proteins have been shown to be cross-reactive with the major peach allergen Pru p 3 and with other lipid transfer protein-containing foods.

An association between grass pollinosis and sensitisation to tomato, potato, green pea, peanut, watermelon, melon, apple, orange or kiwi has been reported.

Orange Allergy Test: Clinical Experience

Orange may induce symptoms of food allergy in sensitised individuals including nausea, pruritis, abdominal cramping, abdominal pain, vomiting, diarrhoea, oral itching, angioedema, dyspnoea, bronchospasm, rhinitis, laryngeal oedema, urticaria, hypotension and anaphylaxis.

Other symptoms have been reported, as illustrated by a study of 29 orange-allergic patients, aged 6 months to 29 years, mainly with symptoms of OAS, but also with eyelid oedema, sneezing, epigastralgia, vomiting, generalised urticaria, throat swelling, atopic dermatitis and chest tightness.

Anaphylaxis to orange may occur uncommonly.

Orange has also been reported to result in contact dermatitis and atopic dermatitis in children.

Other reactions

True allergic reactions that appear to result from contact with orange may be due to environmental exposure to spider mites. This may occur in farmers and orange orchard workers as well as in children and adolescents living in environments leading to sensitisation and to the clinical manifestation of asthma and rhinitis.

Non-allergic reactions may occur to other substances in orange, e.g. aromatic substances and tyramine. Orange has been reported to be one of the most common food causes of migraine. Gustatory sweating due to orange juice has been reported.

Phytophotodermatitis may result from coumarins such as bergapten contained in the orange skin.