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

Grapefruit Allergy Test: Allergen Exposure

Grapefruit is a subtropical citrus tree grown for its fruit, and along with orange and lemon is one of the principal members of the citrus family. Its origin is not clear, but it may originally have been a hybrid of the pomelo and the sweet orange tree. Tangelo is a hybrid of grapefruit and orange, and has a less bitter taste than grapefruit.

Grapefruit is pinkish- to yellow-skinned and oblate to round, ranging in diameter from 10 to 15 cm. The most popular varieties cultivated are referred to by the colour of the segmented pulp, which can be red, white, or pink.

Grapefruit flavour ranges from highly acidic and somewhat bitter to sweet and tart. Unlike other citrus fruits, grapefruit contains mercaptan, a terpene partly composed of sulphur; mercaptan has a strong influence on the taste and odour of the fruit.

Grapefruit Allergy Test: Allergen Description

No allergens from grapefruit have yet been characterised.

In a patient with anaphylaxis from mandarin (Citrus reticulata), a lipid transfer protein was isolated from mandarin fruit. Analysis of the patient’s serum also demonstrated sensitisation to the lipid transfer protein Cit s 3, from orange, as well as to Cit s 1, a germin-like allergen.

Whether similar allergens occur in grapefruit, a closely-related family member, was not assessed.

Grapefruit Allergy Test: Potential Cross-Reactivity

Cross-reactivity within the Rutaceae family (lemon, lime, orange, tangelo) can be expected, but has not been documented to date. Latex allergy has been reported to be associated with allergy to a number of other foods, including avocado, banana, kiwi, papaya, chestnut, peach and grapefruit.

In one case, a 34-year-old female with asthma and atopic dermatitis who developed severe anaphylaxis to latex was described. She was shown to have serum-specific IgE directed against latex, banana, kiwi, grapefruit, and avocado. Skin-specific IgE was also detected to banana, grapefruit, avocado, and latex extract.

Grapefruit Allergy Test: Clinical Experience

Citrus fruits such as grapefruit are among the most common causes of atopic dermatitis. IgE antibodies to grapefruit were detected in patients with atopic dermatitis, allergic rhinitis, and bronchial asthma.

An instance of food-dependent exercise-induced anaphylaxis (FDEIA) attributed to grapefruit has also been reported.

Ingestion and inhalation of pectin, found in grapefruit, can cause hypersensitivity reactions, and allergy to cashew nut, and possibly pistachio, may be associated with pectin allergy.

In a European study of 1,139 individuals across 15 cities, grapefruit was the 18th most often reported food allergen, reportedly resulting in adverse effects in 21% of the cohort. The most common symptoms reported were oral allergy syndrome and urticaria.

Other reactions

Grapefruit contains naringin, bergamottin and dihydroxybergamottin, which can increase the bioavailability and effects of a number of drugs. A single glass of the juice is usually sufficient to produce this interaction. Consumption of grapefruit alongside other medication should be monitored carefully, and under the advice of a physician.