Cashew nut is a food which may result in allergy symptoms in sensitised individuals.

Cashew Nut Allergy Test: Allergen Exposure

The cashew nut is closely related to a number of dermatitis-inducing plants such as poison ivy, poison oak, poison sumac and lacquer sumac.

Originating in Brazil, it is cultivated around the globe, with major exporters of cashew nut including southern India, Mozambique, Tanzania and Kenya.

Cashew nut shell oil causes an immediate vesicant reaction because of its high concentration of phenols. Unaided shelling of the nuts can easily produce painful dermatitis (similar to poison-ivy rashes). Therefore, cashew nuts generate both allergy to cashew nut shell oil and allergy to the nut itself.

Cashew nuts are edible and popular snacks. They are also used as an ingredient in many processed foods such as nut “butters”, bakery and confectionery products, and pesto. They are a common component of oriental foods.

Cashew Nut Allergy Test: Allergen Description

The following allergens present in cashew nut have been characterised to date: a vicilin-like globulin, a major allergen; a legumin-like protein, also a major allergen; an albumin, also a major allergen, and a profilin, the clinical relevance of which has not been evaluated.

Cashew Nut Allergy Test: Potential Cross-Reactivity

Significant cross-reactivity has been reported between pistachio nut and cashew nut.

Cross-reactivity between cashew nut and walnut is possible, as a result of a major allergen in cashew nut which is also present in walnut, and this cross-reactivity is also suggested by in vitro studies.

An early study reported little cross-reactivity between cashew and peanut or Brazil nut. However, a recent study argued that there is a risk of cross-sensitisation.

A recent study reported that cashew nut allergy, and possibly pistachio nut allergy, may be associated with pectin allergy, and the possibility of pectin allergy should be considered in cashew- or pistachio-allergic patients who have unexplained allergic reactions.

Cardol, found in the cashew nut shell, is not usually present in the nut unless contamination occurs. An early study reported cross-reactivity of poison ivy and cashew nut as a result of the nut being contaminated with cardol.

Cashew Nut Allergy Test: Clinical Experience

Cashew nut may commonly induce symptoms of food allergy, atopic dermatitis and other hypersensitivity reactions in sensitised individuals.

Although typically very severe, cashew nut allergy was initially thought to be very rare; however, as cashew nut was initially regarded as a novel food but now is increasing in popularity as a snack, it is regarded as an “emerging” allergen, and hypersensitivity reactions are expected to increase.

Cashew nut allergy is now the second most commonly reported tree nut allergy in the United States.

Besides the protein allergens, cashew nuts contain oleoresins which can cause contact dermatitis and are thought to cause gastrointestinal, systemic and allergic manifestations.

Cashew nut allergy may span a wide age range, and age of onset may vary widely.

Life-threatening anaphylactic reactions to Cashew nut have been reported.

Atopic dermatitis and allergic contact dermatitis from ingestion of or contact with cashew nut have frequently been reported, as well as from contact with the nut shell.

Other reactions

Pollen from the Cashew nut tree may result in sensitisation, asthma and allergic rhinitis.