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

Kiwi Allergy Test: Allergen Exposure

The kiwi fruit originated in China, specifically the Yangtze Valley. Having been cultivated on a small scale over the past few centuries, the main source of the fruit remains from harvesting wild populations. Commercial cultivation does however exist in New Zealand, the United States and France.

The kiwi fruit is oblong or ovoid, up to 8 cm long, and has russet-brown skin densely covered with short, stiff brown hairs. The flesh is usually bright green and mildly acidic in flavour. The tiny, dark-purple or nearly black seeds are relatively unnoticeable when eating.

One variant, the gold kiwi, has a smooth, bronze skin, a pointed cap at one end, and distinctive golden-yellow flesh, with a less tart and more tropical flavour than that of green kiwi. Gold kiwi is less hairy than the green cultivars, and can be eaten whole after rubbing off the thin, fluffy coat, whereas by contrast green kiwi skin is thick and unpalatable.

Kiwis are available year-round, due to controlled storage. The fruits are eaten fresh or may be added to meat dishes, pies, puddings or cakes. As Kiwi contains enzymes similar to Papain, the raw fruit can act as a meat tenderiser. After peeling (usually with lye), fruits are canned, frozen, or freeze-dried.

Kiwi is used in sauces, jams, ice creams, breads and various beverages, including wine. Blending with apple juice or malic acid tends to be important in kiwi processing, for reduction of kiwis’ acidity. The underripe fruits, which are high in pectin, are chosen for making jelly, jam and chutney.

Kiwi Allergy Test: Allergen Description

At least 12 allergenic proteins have been detected in Kiwi fruit. The protein content of kiwi increases during the ripening process. In green kiwi, actinidin and kiwellin were the major components. Thaumatin-like protein was found in high amounts in both green and gold kiwi. Variations in the relative amounts of the proteins, as well as new protein bands, were seen during the ripening process of green kiwi and, to a lesser extent, of gold kiwi.

Green and gold kiwi extracts were shown to be highly cross-reactive in inhibition studies.

Kiwi Allergy Test: Potential Cross-Reactivity

Extensive cross-reactivity between the different individual species of the genus could be expected; but manifestations are variable, depending on allergen composition.

The association of kiwi allergy with allergies to pollen and latex has been described, and cross-reactivity has been confirmed by inhibition studies with birch pollen, Timothy pollen, avocado, banana, latex, rye, and hazelnut.

Kiwi allergy has also been associated with grass allergy.

Kiwi Allergy Test: Clinical Experience

The most common symptoms attributed to kiwi allergy are those associated with oral allergy syndrome, which include pruritis of the eyes, ears, tongue, pharynx and mouth, and swelling of the lips, tongue and pharynx. Nausea, vomiting, diarrhoea, abdominal pain, asthma, angioedema, allergic contact dermatitis, atopic dermatitis and contact urticaria have also been reported.