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

Carrot Allergy Test: Allergen Exposure

Carrots are a root vegetable which is native to Europe. The carrot plant is a close relative of the parsley plant and has similar delicate green foliage. The roots are long, fleshy and orange and can be eaten raw or cooked. The wild carrots from which modern cultivars are descended have relatively small and woody roots, but selective breeding has improved the edible yield over hundreds of years.

Carrot is used in a wide range of foods, including soups and stews. It is rich in sugar and has been renowned for over 2000 years for health-giving properties, and recently for high vitamin A content.

Carrot Allergy Test: Allergen Description

Various allergens present in carrot have been detected, including a Bet v 1-homologue (a major allergen), a heat-stable lipid transfer protein (LTP), a profilin and a 20 kDa protein.

The presence of cross-reactive carbohydrate determinants (CCDs) has also been reported.

Carrot lipid transfer protein, thought to be relevant in carrot allergy, is not present at detectable levels in the edible parts of carrot. The absence of this protein may explain why carrot allergy is very rare in Mediterranean, countries, where LTP sensitisation is common.

Carrot Allergy Test: Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the Apiaceae family could be expected. Members include carrot, celery, fennel, anise, caraway, dill, lovage and parsley.

Hypersensitivity to carrot is also frequently associated with sensitisation to birch and mugwort pollen.

Cross-reactivity between mango, mugwort pollen, birch pollen, celery, and carrot has been reported.

Profilin, a ubiquitous cross-reacting plant allergen related to Birch pollen Bet v 2, is also present in Carrot and may result in cross-reactivity.

Carrot contains a lipid transfer protein, which may cross-react with LTP from several other plant-derived foods including peach peel, broccoli, apple, walnut, hazelnut, peanut, corn, rice and beer.

Carrot does share allergens with lettuce, although carrot allergens are more potent than those of lettuce.

Carrot Allergy Test: Clinical Experience

Carrot commonly induces symptoms of food allergy, oral allergy syndrome, and asthma in sensitised individuals. Carrot allergy may occur in the elderly.

Carrot allergy has been reported to affect up to 25% of food-allergic subjects. In a Swiss study, carrot was found to be the third-most-common food allergen, affecting 13% of food-allergic patients, and was more common than allergy to hen’s egg or fish.

The most frequently reported symptoms are oral allergy syndrome, but other symptoms include angioedema, urticaria, dyspnoea, vertigo, tightness of the throat or chest, dysphagia, hoarseness, conjunctivitis and rhinitis. Carrot has also been reported to result in eosinophilic cystitis.

Anaphylaxis resulting from allergy to carrot has been reported.

Other reactions

Phytophotodermatitis is a phototoxic dermatitis resulting from contact with psoralen-containing plants such as celery, limes, parsley, figs, and carrots.

Carrot has been reported to have monoamine oxidase inhibiting activity.

Consuming large quantities of Carrots may result in inadvertent increased vitamin A intake, which may cause papilloedema.