f86 Parsley

f86 Parsley Scientific Information

Type:

Whole Allergen

Display Name:

Parsley

Route of Exposure:

Ingestion

Family:

Apiaceae

Species:

Petroselinum crispum (Mill.) Fuss

Latin Name:

Petroselinum crispum

Summary

Parsley, a member of the Apiaceae family, is an herb frequently used in salads, sandwiches and cooked dishes. Despite its frequent consumption, allergic reactions to parsley are rare and are limited to individual case reports. Nevertheless, symptoms of urticaria–angioedema, contact dermatitis and anaphylaxis have all been described after eating or skin contact with parsley.

Allergen

Nature

Parsley is an herbaceous plant cultivated in many European countries, including Germany, France, Holland and the UK, and can grow in both tropical and cold climatic conditions. Despite its frequent consumption, allergic reactions to parsley are rare. Case reports of urticaria–angioedema, contact dermatitis and anaphylaxis have been described after eating or skin contact with parsley (1).

Taxonomy

Taxonomic tree of parsley (2)
Domain	Eukaryota
Kingdom	Plantae
Phylum	Tracheophyta
Subphylum	Spermatophytina
Class	Magnoliopsida
Order	Apiales
Family	Apiaceae
Genus	Petroselinum Hill

Route of Exposure

Main

Ingestion.

Clinical Relevance

Reports of allergic reactions to parsley are limited to individual case reports. A 41-year-old woman experienced a near-fatal anaphylactic attack after parsley ingestion. Initially she experienced itching, abdominal pain, difficulty breathing and palpitations, followed by severe angioedema of the eyes and lips, generalized urticarial plaques and loss of consciousness upon admission to hospital. The symptoms were controlled with epinephrine, antihistamines, intravenous fluid and oxygen therapy. Sensitivity to parsley was confirmed via skin prick testing (3).

Another case report detailed a 26-year-old woman who presented with acute rhinoconjunctivitis, facial swelling, otic and oropharyngeal pruritus, and itchy hands and feet within 5 minutes of eating a sauce containing parsley. Treatment with intramuscular corticosteroids and antihistamines led to improvement of symptoms within a few hours. Subsequent skin prick testing elicited a positive response to parsley (4 mm wheal) and levels of specific IgE antibodies against parsley were also found (1). A 24-year-old woman with a history of seasonal rhinoconjunctivitis described episodes of lip angioedema after the consumption of foods containing raw parsley, as well as the occurrence of itchy erythematous-edematous lesions of the hands after contact with uncooked parsley leaves. The patient did not report any symptoms after the ingestion of cooked parsley. Skin prick tests were performed with parsley allergen extract eliciting a strong positive reaction (12 mm wheal) (4). Additionally, in a study of 14 atopic patients with positive skin prick reactions to mugwort, 12 patients also showed sensitivity to parsley (5).

Molecular Aspects

Allergenic molecules

Table adapted from Allergome.org (6)

Allergen	Type	Mass (kDa)
Pet c 1	Pathogenesis-related (PR) protein A; phosphatase inhibitor	16.5
Pet c 2	Profilin; actin binding protein	14
Pet c 3	Lipid transfer protein	12

A low-molecular-weight lipid transfer protein allergen of 12 kd (Pet c 3) has been identified as a possible cause of parsley allergy (1).

Cross-reactivity

One patient with parsley allergy was also found to have specific IgE to the major peach allergen, Pru p 3. Therefore, cross-reactivity with peach is a possibility (1).The major birch pollen allergen Bet v 1 has many homologues causing cross-reactivity, including Pet c 1 (6, 7).

Compiled By

Author: RubyDuke Communications

Reviewer: Dr. Christian Fischer

Last reviewed:May 2022

References

Cordobés-Durán C, García-Menaya JM, Lombardero M, Ledesma A, Bobadilla P. Detection of a 12-kilodalton lipid transfer protein allergen in parsley. J Investig Allergol Clin Immunol. 2007;17(4):282-3.
ITIS. Petroselinum crispum 2021 [cited 2022 06.01.21]. Available from: https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=822347#null.
Arslan S, Ucar R, Caliskaner AZ. A Cases of Near-fatal Anaphylaxis: Parsley "Over-use" as an Herbal Remedy. Med Arch. 2014;68(6):426-7.
Foti C, Cassano N, Mistrello G, Amato S, Romita P, Vena GA. Contact urticaria to raw arugula and parsley. Ann Allergy Asthma Immunol. 2011;106(5):447-8.
Kauppinen K, Kousa M, Reunala T. Aromatic plants–A cause of severe attacks of angio-edema and urticaria. Contact Dermatitis. 1980;6(4):251-4.
Allergome. Parsley 2021 [cited 2022 06.01.22]. Available from: http://www.allergome.org/script/search_step2.php.
Matricardi PM, Kleine-Tebbe J, Hoffmann HJ, Valenta R, Hilger C, Hofmaier S, et al. EAACI Molecular Allergology User's Guide. Pediatr Allergy Immunol. 2016;27 Suppl 23:1-250.