Brief communication

Bronchial asthma, rhinoconjunctivitis, and contact dermatitis caused by onion

Potentially harmful plants grow almost everywhere, hence, it is not practical to eradicate them all. However, a basic understanding of adverse cutaneous reactions and the common plants that cause each type can enable vulnerable individuals to discover the source of their dermatitis and thus prevent re-exposure. The aim of this study therefore, was to document the plants responsible for irritant contact dermatitis (ICD) in the Eastern Cape, along with their respective irritants and clinical presentations.

Study participants (161) in 12 locations were selected by convenient sampling with particular focus on local people who regularly interact with plants or plant products. Interview questions were focused on the local names of plants that contain irritating chemicals and physical characteristics that cause ICD.

Forty four plant species distributed in 24 families and 34 genera were reported as causative agents of irritant contact dermatitis. Herbs constituted 67.35%, trees 24.49% and shrubs 8.16%. Mechanical ICD was reported to be caused by 23 species, closely followed by chemical ICD (20 species) and mechanico-chemical ICD (6 species). Species with the highest frequency of citations were Allium cepa, Acacia karroo, Capsicum annuum, Citrus limon and Zea mays. The most representative families were Euphorbiaceae (for chemical ICD), Urticaceae (for mechanico-chemical ICD), Fabaceae and Rutaceae for mechanical ICD. Most of the classes of chemical compounds identified as being responsible for chemical ICD were restricted to plants of specific genera such as the diterpenes in Euphorbia spp., disulphides in Allium spp., terpenes in Citrus spp. and isothiocyanates in Brassica spp.

Thorns and hairs were reported for causing Mechanical ICD in 6 plant species each, including widely cultivated plants such as Acacia karoo and Citrus reticulata.

Irritant contact dermatitis is a common cutaneous disorder in individuals exposed to plants in the Eastern Cape, especially among workers of the food and flower industries. Health practitioners should therefore consider the possible work-related causes of dermatitis, especially in cases associated with a clear history of symptoms.

La rareté des allergies aux Liliacées justifie cette relation de cinq cas d’anaphylaxie alimentaire sévère à l’oignon et à l’ail. Trois femmes ont présenté un choc anaphylactique de grade 3, deux ont présenté une diarrhée aiguë. La fréquence, évaluée sur 1300 cas d’anaphylaxie alimentaire enregistrés est de 0,38 %. L’allergie est isolée. Le diagnostic est porté par l’anamnèse relevant la fréquence d’épisodes allergiques et l’interrogatoire permettant d’identifier la responsabilité de l’oignon. Les prick-tests à l’oignon natif et la recherche d’IgE spécifiques sont négatifs quatre fois sur cinq, et trois fois sur quatre. Les auteurs avancent l’hypothèse que l’allergène majeur, l’alliine lyase, est en quantité trop faible dans l’oignon pour que les tests avec la source allergénique puissent être efficients.

The paucity of cases of allergy to onion or to garlic justifies this series of five cases of severe food anaphylaxis to onion. Three females had an anaphylactic shock and two had an acute diarrhea. The prevalence is estimated 0.38% (out of 1300 cases of anaphylaxis registered). All of them had only this food allergy, leading to suspect that the allergen is restricted to liliaceae. Four over five prick-tests were negative and three-quarter of specific IgEs were not detected. The authors suggest that the poor efficiency of allergy tests to onion is due to a weak amount of alliin lyase, the major allergen, in the allergenic source.

Les horticulteurs et pépiniéristes côtoient de multiples substances tant dans le domaine végétal que dans le domaine chimique et toutes ces substances sont potentiellement allergéniques. Le contact peut entraîner des manifestations allergiques cutanées et la voie inhalée des symptômes respiratoires. Les végétaux sont probablement plus impliqués dans les allergies de contact alors que les produits chimiques induisent sans doute les deux types de symptômes. Ces données de la littérature méritent toutefois peut-être quelques réserves du fait du manque de standardisation des tests diagnostiques. Ne seront évoqués que les symptômes respiratoires.

Horticulturists and nursery workers are in frequent contact with many plant and chemical substances that are potentially allergenic. Skin contact can lead to cutaneous manifestations and inhalation can lead to respiratory symptoms. Plant substances are probably more important as causes of contact allergies whereas chemicals can induce both cutaneous and respiratory symptoms. Published data point, however, to reservations regarding diagnosis due to the lack of standardized diagnostic tests. Here, we will consider only those substances that cause respiratory symptoms.

La familia de las liliáceas ha sido implicada en el desarrollo de rinoconjuntivitis y asma bronquial ocupacional. Presentamos un paciente con síntomas cuando manipulaba especias, incluyendo ajo y cebolla en polvo

Se realizan test cutáneos con inhalantes, especias comerciales, liliáceas en fresco y con extractos de polvo de especias. Se determinó IgE especifica (CAP-Pharmacía) y se realizó Immunoblotting con ajo

Se llevo a cabo control de pico flujo (PEF) en la zona de manipulación de especias y en la zona de transporte del producto envasado

Se realizó test de provocación nasal con el ajo y la cebolla y se midió la obstrucción nasal mediante rinomanometría anterior activa (RAA)

Los test cutáneos fueron positivos con el polvo de ajo, cebolla, y con las liliáceas en fresco. La IgE específica fue positiva para ajo y cebolla. El immunoblotting mostró dos bandas de fuerte intensidad correspondiente a 14 y 40 KD con el extracto de ajo

Se objetivó un aumento de la resistencia nasal superior al 100 % con ambos extractos

The Liliacea family has been implicated as a cause of occupational rhinoconjunctivities and bronchial asthma. We report a patient who presented symptoms when he manipulated spices including garlic and onion dusts. Nasal challenge test with active anterior rhinomanometry was used for the diagnosis

Skin-prick tests with common inhalants, commercial spices, fresh Liliaceae and powdered spices diluted in saline solution (10 mg/ml) were performed. Immunoblot and specific IgE (CAP-Pharmacia) were determined. Control peak expiratory flow was monitored during a period at work in an area where spices were manipulated and in an area where they were transported. Nasal challenge test with garlic and onion powder was performed. The resulting nasal obstruction was measured as nasal airway resistance and was determined by rhinomanometry

Skin-prick tests were positive for onion, garlic powder and fresh Liliacea. Specific IgE were positive for garlic and onion. IgE immunoblotting showed very strong bands at 14 and 40 kD with garlic extract. Nasal challenge showed an increase in inspiratory nasal resistance which was higher than 100 % of the basal value for both onion extract and garlic