Parsley is a herb which may result in allergy symptoms in sensitised individuals.

Parsley Allergy Test: Allergen Exposure

Parsley is a garden herb which is a biennial in temperate regions, or an annual in the subtropics or tropics. It is widely used in Middle Eastern, European, Brazilian, and American cooking.

The two main groups of parsley used as herbs are French, or curly leaf parsley and Italian, or flat leaf parsley. The former is commonly used as a garnish, either whole or chopped, and features in many stocks, salads, soups, and sauces.

Parsley is commonly used in bouquet garni, a bundle of herbs used to flavour various dishes. In the UK, parsley sauce is often served with fish or gammon. It is a key ingredient of the Italian salsa verde, as well as the Brazilian cheiro-verde.

In the Middle East, parsley is a main ingredient in salads such as the Lebanese tabbouleh; it is also often mixed in with chickpeas and/or fava beans while making falafel, lending a green colour to the mixture.

Root parsley is also commonly encountered in various European cuisines, where it is an ingredient in many soups, stews, and casseroles, as well as being eaten alone as a snack.

Parsley is a good source of flavonoids and antioxidants, especially luteolin, apigenin, folic acid, vitamin K, vitamin C, and vitamin A.

Parsley Allergy Test: Allergen Description

No allergens present in parsley have been characterised to date. Although the presence of an allergen related to Bet v 1, the major Birch pollen allergen has been demonstrated, no allergenic characteristics have yet been reported.

Other studies have also suggested the presence of a Bet v 1-like allergen in Parsley, but with the implication that this may be an important Parsley allergen.

Parsley Allergy Test: Potential Cross-Reactivity

An extensive but variable degree of cross-reactivity among the different individual species of the family Apiaceae could be expected.

Although a Bet v 1-like allergen has not been isolated from Parsley to date, cross-reactivity studies have by implication suggested the presence of this allergen, and therefore suggest cross-reactivity among plants containing this panallergen.

It may be responsible for cross-reactivity reported in an individual with allergy to celery resulting in urticaria, oedema, and anaphylaxis, who displayed sensitivity to parsley, carrot and ragweed.

Parsley Allergy Test: Clinical Experience

Parsley may commonly induce symptoms of food allergy in sensitised individuals, in particular in individuals with allergic rhinitis from a pollen allergy. Symptoms include nasal and eye itchiness, laryngeal oedema, wheezing and common symptoms of food allergy.

Anaphylaxis and severe attacks of angioedema and urticaria have been reported.

Contact dermatitis from Parsley has been reported. Occupational dermatitis in gardeners following exposure to Parsley has also been described.

Other reactions

Excessive consumption of parsley should be avoided by pregnant women. Normal food quantities are safe for pregnant women, but consuming excessively large amounts may have uterotonic effects.

Parsley in an herbal product was reported to potentially increase the risk of bleeding or potentiate the effects of warfarin therapy.

It has also been demonstrated to have a diuretic effect.