Barley Allergy Test
Latin name: Hordeum vulgare
Source material: Untreated planting seeds
Family: Poaceae (Gramineae)
Common names: Barley, Barleycorn
Barley is a food which may result in allergy symptoms in sensitised individuals.
Barley Allergy Test: Allergen Exposure
Barley ranks fourth among the world’s grain crops in total tonnage harvested per annum, after wheat, rice and maize. Originating in the Middle East, it has been used by humans since prehistoric times. Today, the two main uses of barley are as animal feed, or when malted, as a base ingredient in the brewing and distilling of beers and spirits.
Like other grain crops, barley is a grass which yields grain in the form of bristled spikes or ‘ears’. It is grown worldwide, with the top producers being Russia, France and Germany.
Around half of the global harvest is used in malting, but the grain is also used as an additive to bulk out soups, stews and baby food due to its mild flavour and soft texture when cooked.
In terms of beverage production, barley is most commonly used for beers of various types as well as whisky.
When combined with water and lemon, pearl barley is used to make barley water, an old-fashioned restorative for invalids. Barley is a good source of B vitamins and some minerals.
Barley Allergy Test: Allergen Description
A number of allergens present in barley have been characterised, among them are an alpha-amylase/trypsin inhibitor, an alpha-amylase, a beta-amylase, hordein and a lipid transfer protein.
Residual allergens in beer may result in allergic reactions. Because of the severity of allergic manifestations to beer, research recommends testing for sensitivity to this beverage those atopic patients who are positive to malt/barley and/or who exhibit urticarial reactions after drinking beer.
Barley Allergy Test: Potential Cross-Reactivity
An extensive cross-reactivity among the different individual species of the genus could be expected. Cross-reactivity with other species within the Poaceae family can be expected, as well as with other species within the genus Triticum.
Cross-antigenicity has been demonstrated among wheat, triticale, rye, barley, oat, rice and maize.
Cross-reactivity among plants containing lipid transfer protein (LTP) is possible but would depend on the specific plants. For example, the lipid transfer protein from maize was shown to completely cross-react with rice and peach lipid transfer proteins but not with wheat or barley lipid transfer proteins.
Barley Allergy Test: Clinical Experience
Barley may commonly induce symptoms of food allergy in sensitised individuals.
Symptoms may include gastrointestinal distress, atopic dermatitis and urticaria, angioedema, anaphylaxis and food-dependant, exercise-induced anaphylaxis, wheezing and baker’s asthma.
Coughing, wheezing, shortness of breath, fever, stuffy nose, and skin itching/rash on exposure to grain dust have also been reported, as well as “grain fever”.
Anaphylaxis following the ingestion of barley may occur. These reactions may be to residual barley proteins in beer.
Food-dependent exercise-induced anaphylaxis may result from ingestion of barley.
Barley may also result in occupational allergy in bakery and other food industry workers, liqueur and spirit manufacturers, and farmers. Occupational asthma may also occur to barley grain dust.
Barley may result in or exacerbate atopic dermatitis or contact dermatitis.
Six cases of acute exogenous allergic alveolitis after loading mouldy barley have been reported.