Kumquat is a fruit in the Rutaceae family of plants, making it a lesser known citrus fruit. Other plants in this family include lemon, limes, oranges and grapefruits.

The peel of most citrus fruits contains limone which is associated with contact allergic dermatitis. Limonene is a well known skin irritant - so may cause sufferers to react to the skin whilst being able to eat or drink the fruit.

There is an increasing amount of research into citrus seed allergy - it has been suggested that some allergic reactions have been triggered not by the fruit or peel, but by accidental consumption of the seeds. These allergic reactions may be triggered by proteins found in more commonly eaten seeds (like sunflower and pumpkin seeds) - seed storage proteins.

Like other citrus fruits kumquat 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.

Other citrus fruits are low FODMAP foods. 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.

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

Kumquat allergy is linked to allergic contact dermatitis.

Eating kumquats is also associated with phytophotodermatitis. This is a skin condition that occurs when a person gets the juice from the fruit on the skin and doesn't wash it off. The furocoumarins in the juice of the fruit are activated by the sun and cause an itchy rash on the skin.

Other foods in the Rutaceae family of foods are grapefruit, lemon, lime, orange, sichuan pepper and tangerines. If allergic to one of these you may want to avoid eating foods from this list. Citrus fruits are all in the Citrus genus of plants (with the exception of the sichuan pepper), so are very closely related.

Note that these food lists are not exhaustive, the most up to date information is on the Cross Reactivity Tool.

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