Table of Contents

Whole Allergen

f226 Pumpkin seed

f226 Pumpkin seed Scientific Information

Type:

Whole Allergen

Display Name:

Pumpkin seed

Allergen code:

f226

Family:

Cucurbitaceae

Species:

Cucurbita pepo Cucurbita maxima

Route of Exposure:

Ingestion

Latin Name:

Cucurbita pepo

Other Names:

Field pumpkin, Naked-seeded pumpkin, pumpkin, Courgette, Summer squash, Winter squash, Zucchini

Synonyms:

C. moschata, C. maxima, C. mixta, Cucumis pepo

WHO/ICD-11 code:

XE8XA

(ICD-11 is currently under implementation by WHO and the ICD-11 codes displayed in the encyclopedia may not yet be available in all countries)

Summary

Pumpkin (Cucurbita pepo) is a common fruit of an herbaceous creeper plant belonging to the family Cucurbitaceae. It is considered native to the USA (Eastern and Southwestern) and Northern Mexico. Cucurbita species are one of the most popular foods consumed worldwide and are used in several cuisines. The prevalence of pumpkin seed (C. pepo)-related food allergy is rare and is limited to a few case reports. However, oral ingestion of pumpkin seeds (either whole or in food preparations) can manifest symptoms ranging from oral allergy syndrome to respiratory symptoms and anaphylaxis. In pumpkin seed (C. maxima), Cuc ma 4 (50 kDa non reducing) and Cuc ma 5 (14 kDa) are identified as allergenic molecules. Additionally, another study has also reported the presence of a panallergen profilin (14 kDa) in the pumpkin seeds (C. pepo). Furthermore, pumpkin seeds are found to be cross-reactive with melon seeds, cashew nuts, and birch pollen.

Allergen

Nature

Pumpkin (Cucurbita pepo) is a common fruit of an herbaceous creeper plant. This fruit usually grows on vines and may attain a length of around 7.92 m (1, 2). The seeds are white, smooth, flattened, and oval with a size of 1–1.5 cm × 0.5–1 cm (3). The harvesting season for pumpkins is late summer, where the seeds are separated from the pulp and stored for further use (1). Dried pumpkin seeds can be used as a thickening agent for soups or as a snack. Additionally, the pumpkin seeds' by-products, including oil and flour, are used in various applications and contain nutritional benefits (4).

Taxonomy

According to the ITIS database, there are around 34 genera in the Cucurbitaceae family and 99 species (5).

Taxonomic tree of Pumpkin (Cucurbita pepo) (6)
Domain	Eukaryota
Kingdom	Plantae
Phylum	Spermatophyta
Subphylum	Angiospermae
Class	Dicotyledonae
Order	Violales
Family	Cucurbitaceae
Genus	Cucurbita
Species	Cucurbita pepo

Epidemiology

Worldwide distribution

Seed allergies have been reported to be increasing worldwide; however, the prevalence of pumpkin seed (C. pepo)-related food allergy is rare and is limited to a few case reports (7-9).

Environmental Characteristics

Living environment

Cucurbita species thrive in terrestrial and wetland environments, preferring warm weather with 18–27ºC temperatures for maximum crop production. The seed germination needs soil temperatures above 16ºC, and it takes approximately 14 days for the crop to leaves at this temperature. A wide range of well-drained fertile soil types (pH range between 6.0 to 6.5) can be beneficial for the growth of Cucurbita species (2).

Worldwide distribution

Pumpkins (Cucurbita species) are regarded as one of the most popular foods consumed worldwide and are believed to be originating from temperate North America (1, 10). However, C. pepo is considered to be native to the USA (Eastern and Southwestern) and Northern Mexico (2). Pumpkins are cultivated globally due to their extensive usage in several cuisines (1). Cucurbita

species are reported to be mainly grown in temperate, subtropical, and tropical regions of the world (2). Pumpkin seeds are found to be extensively consumed in Greece and some parts of Africa and Brazil. Furthermore, in Austria, the pumpkin seed oil is used to season salads (4).

Route of Exposure

Main

Ingestion of pumpkin seeds is considered the route of exposure (8). In addition, inhalation of pumpkin seed flour has also been reported to be responsible for pumpkin seed-related food allergy (8).

Clinical Relevance

Pumpkin seed allergy can manifest symptoms ranging from oral allergy syndrome to respiratory symptoms and anaphylaxis (11, 12).

Oral allergy syndrome

A study confirmed oral allergy syndrome in a patient along with abdominal pain after consumption of pumpkin seeds (C. pepo) [based on in vitro testing, prick by prick (PP), and skin prick testing (SPT)] (12).

Respiratory symptoms

Allergic symptoms (oropharyngeal swelling and itching, and bronchial asthma) were observed in 3 fishermen (29-49 years) after consuming food containing pumpkin seeds. The patients were found to exhibit hypersensitivity to pumpkin seeds (confirmed through PP, in vitro testing, and SPT) (8)

Anaphylaxis

A study confirmed anaphylaxis (based on PP, skin prick testing SPT, and in vitro testing) in 2 patients after ingestion of pumpkin seeds (C. pepo) (12).

Another study reported immediate allergic reactions with severe and systemic symptoms like anaphylaxis in 4 patients (12-32 years). All the patients exhibited a positive specific IgE and SPT towards pumpkin seeds (C. maxima) extract (11).

A case report concerning a 4-year-old girl with a history of asthma also revealed anaphylactic reactions after consuming pumpkin (C. maxima) seeds (confirmed through SPT) (13). Additionally, anaphylaxis was also observed in a 70-year-old woman after consuming pumpkin (C. maxima) seeds confirmed through SPT (14).

Prevention and Therapy

Prevention strategies

Avoidance

Complete avoidance of pumpkin seeds and pumpkin-based food from the diet can be considered as preventive measures for pumpkin seed allergy (15, 16).

Molecular Aspects

Allergenic molecules

According to WHO/IUIS (to date 23-Sep-2021), Cuc ma 4 and Cuc ma 5 have been identified and listed as allergenic molecules from pumpkin (C. maxima) and are represented in the table below (17).

Name	Biochemical name	Molecular weight (kDa)
Cuc ma 4	11S globulin	50 kDa non reducing; 35 kDa and 23 kDa reducing
Cuc ma 5	2S albumin	14 kDa

A study reported the presence of a homolog of a panallergen profilin (14 kDa) in pumpkin seeds (C. pepo) confirmed using immunoblot (8).

Biomarkers of severity

Cuc ma 5 (a 2S albumin) is regarded as a diagnostic marker of sensitization and severe reactions. Cuc ma 4 has also been reported as a marker for both symptom severity and cross-reactivity with other vegetable sources (11).

Cross-reactivity

Cuc ma 4 is cross-reactive with melon seeds and cashew nuts (11).

Another study reported cross-reactivity between the profilin present in pumpkin seeds (C. pepo) and birch (8).

Compiled By

References

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Bueno-Diaz C, Martin-Pedraza L, Leon L, Haroun-Diaz E, Pastor-Vargas C, Munoz-Garcia E, et al. 2S albumins and 11S globulins, two storage proteins involved in pumpkin seeds allergy. Allergy. 2020;76(1):383-6.
Marcela Valverde-Monge BB, Javier Custa-Herranz, Manuel De las Heras. Allergy to Pumpkin Seeds. J ALLERGY CLIN IMMUNOL. 2017;139.
Alsukait SA, Abdullah. Anaphylaxis secondary to ingestion of pumpkin seeds in a child: A case report. Journal of Nature and Science of Medicine. 2019;2.
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