Fig Allergy Test
Latin name: Ficus carica
Source material: Fresh fruit
Common names: Fig, Common fig, Edible fig
Fig is a food, which may result in allergy symptoms in sensitised individuals.
Fig Allergy Test: Allergen Exposure
Figs have been cultivated by humans for thousands of years, principally in western Asia and the Mediterranean regions. The fruits are now also grown in China, Japan, India, South Africa, Australia, and North and South America. The family of fig plants includes ornamental varieties as well as rubber producing species, alongside the fruit bearing cultivars. In total around 700 varieties have been catalogued.
The fruit of the fig develops from a swollen flower stalk, which expands over time to form a 5cm diameter pear shaped fruit. Some varieties bear fruit without external pollination, others are pollinated by specialised wasps which crawl into the fruit itself. The ostiole, or hole, which allows access to the wasp can also let in rain water, occasionally leading to figs fermenting while still on the plant.
Figs are consumed fresh and raw, as a whole fruit including the peel. They are also commonly preserved by canning, stewing or drying and have long been a popular addition to pies, puddings, cakes, bread or other bakery products, and even added to ice cream mix. The fruits are sometimes preserved in sugar syrup or prepared as jam, marmalade, or paste.
Fig Allergy Test: Allergen Description
Several allergens present in fig have been characterised, including a profilin, a protease and a lipid transfer protein.
In jelly fig (Ficus awkeotsang), a related family member, 2 thaumatin-like protein isoforms were isolated, as well as a pectin methylesterase and a chitinase in the jelly fig curd. Whether similar allergens are present in fig has not been determined to date.
Fig extracts lose most of their allergenicity when denatured by heat (95°C), but allergic reactions to fresh or dried figs are possible.
Fig Allergy Test: Potential Cross-Reactivity
An extensive cross-reactivity among the different individual species of the genus could be expected, but this has not been fully investigated to date.
An early report of 8 individuals allergic to fig stated that skin tests with related allergens (Ficus benjamina, mulberry pollen, latex, kiwi, papain and bromelin) were positive with Ficus benjamina in all eight patients, with kiwi in 3, and with latex and papain in one patient each.
Sensitisation to fig with cross-sensitisation to weeping fig and natural rubber latex has been reported. Fig has also been included among those plant foods responsible for ‘latex-fruit syndrome”, an allergic disease resulting from cross-sensitisation to latex (Hevea brasiliensis) and several types of fruits including papaya, avocado, banana, chestnut, passion fruit, fig, melon, mango, kiwi, pineapple, peach, and tomato.
Fig Allergy Test: Clinical Experience
Fig may induce symptoms of food allergy in sensitised individuals. Symptoms include pruritis, generalised urticaria, facial angioedema, asthma, gastrointestinal symptoms, oral allergy syndrome, and anaphylaxis.
A study was conducted at 17 clinics in 15 European cities, and among 1,139 individuals, fig was the 68th-most reported food resulting in adverse effects, with 6.7% of participants naming it as a cause of symptoms.
The latex of the unripe fruits and of any part of the tree may be severely irritating to the skin and eyes if not removed promptly. It is an occupational hazard not only to fig harvesters and packers, but also to workers in food industries, and to those who employ the latex to treat skin diseases. Cutaneous reactions may mimic a burn injury.