Green Bean Allergy Test
Latin name: Phaseolus vulgaris
Source material: Fresh beans
Family: Fabaceae (Leguminosae)
Common names: Green bean, Common bean, French bean, String bean, Snap bean, Wax bean, Haricot bean
Green bean is a food which may result in allergy symptoms in sensitised individuals.
Green Bean Allergy Test: Allergen Exposure
The green bean is one of many edible varieties in the Phaseolus genus, and is characterised by its long slender pods containing a single row of small seeds. Both the seeds and the pod itself are edible, although as the pods mature they become more fibrous, and are therefore generally eaten boiled or steamed rather than raw.
The young leaves can also be eaten raw or cooked as a potherb.
Green beans have traditionally had a number of medicinal uses. The green or dried mature pods, or the seeds alone, are diuretic, hypoglycemic and hypotensive. When ground into flour, the seeds are also used as a homeopathic remedy.
Green Bean Allergy Test: Allergen Description
No allergens present in green beans have yet been characterised. A chitinase which resembles that found in avocado (where it is a major allergen) has been isolated. This allergen was completely inactivated by heating.
It is thought that green bean contains heat-labile and heat-stable allergens. A 20-year-old girl who experienced anaphylaxis to green bean had reacted to boiled green bean, which induced a stronger reaction than raw green bean.
A common feature of most legume allergens, which would include those present in green beans, is a natural resistance to thermal, chemical, and, in some respects, proteolytic denaturation.
Green Bean Allergy Test: Potential Cross-Reactivity
An extensive cross-reactivity among the different individual species of the genus could be expected but in fact does not occur frequently. Indeed, clinical studies have found that there is little cross-reactivity between members of the legume family.
In a study of 39 Spanish children the legumes white bean and green bean and soy were well tolerated by children allergic to other legumes.
Green Bean Allergy Test: Clinical Experience
As a member of the legume family, the green bean may often result in symptoms of food allergy. Allergic reactions caused by skin contact or by inhalation of vapor from raw or boiling green bean have also been reported.
Asthma and rhinitis were reported in 3 women after exposure to raw green bean. All women tolerated ingestion of cooked green beans. Multiple episodes while handling these vegetables for cooking were reported.
Similar symptoms were reported in another patient, who experienced rhino-conjunctivitis, occupational asthma, and contact urticaria while trimming raw green beans or inhaling vapour from boiling green beans. She was able to eat and touch cooked green beans without any ill effect and showed no reactivity to any other foods.
In an atopic housewife, rhino-conjunctivitis and acute asthma associated with unrelated family members, green bean and Swiss chard, have been reported.
Severe reactions to green bean have been reported. Anaphylaxis was described in a 20-year-old girl, which occurred 1 hour after ingestion of green beans. Her symptoms included gastroenteritis, generalised urticaria and collapse.
Occupational contact dermatitis caused by the leaves of Phaseolus plants has been reported in a farmer.