Barley
Summary
Barley, a self-pollinating crop belonging to the Poaceae family, is an annual monocotyledonous herb. The flowering period of barley typically ranges from June to July. It is native to North Africa and western Asia and is regarded as a sustainable crop in Europe, Africa, Asia, and America. It thrives best in the temperate climate; well-drained clay loams and loams are considered optimal for its cultivation. Exposure to barley pollen has been reported to cause respiratory symptoms in atopic individuals. Hor v 5, a 30 kDa protein, has been identified as an allergenic molecule present in barley pollen. Furthermore, barley pollen has been found to be cross-reactive with Kentucky bluegrass, perennial ryegrass, maize, rye, triticale, common wheat, oat, rapeseed, common sunflower, and flax.
Epidemiology
Worldwide distribution
Around 20% of the general population and almost 40% of the atopic individuals are impacted by allergic sensitization due to grass pollens.
According to an Ireland-based study, the West Meath region has been reported to have a high prevalence of barley sensitization among patients with symptomatic rhinitis (19%) as 30% of the production of Irish barley is yielded from this region.
A study conducted in Turkey reported sensitization to barley pollens among 19.5% (105/539) of children with respiratory allergy.
Risk factors
People (like farmers) with direct exposure to cultivated grass fields (Hordeum, Triticum, Secale) or residing in proximity to these fields can develop sensitivity and allergic symptoms.
Route Of Exposure
Main
The route of exposure for barley pollens is through inhalation.
Clinical Relevance
Poaceae family has been reported to produce a large amount of pollen in the air, thus resulting in respiratory allergies. Barley has been reported to cause respiratory symptoms.
Respiratory symptoms
According to a New Zealand-based study conducted on 167 farmers, barley crop exposure was found to be responsible for respiratory symptoms like breathing problems (31.1%), shortness of breath (18.9%), chronic bronchitis (14.4%), and organic dust toxic syndrome (13.2%).
Prevention And Therapy
Prevention strategies
Avoidance
One of the main measures to be taken is to cut down the amounts of pollen in the respiratory system. During pollen season, allergic patients are suggested to stay indoors or wear a mask outdoors to avoid pollen allergens. In worsening conditions, patients may be advised to move to a non-pollen area.
Cross-Reactivity
According to a study, barley pollen has been found to be cross-reactive with Kentucky bluegrass (Poa pratensis), perennial ryegrass (Lolium perenne), maize (Zea mays), rye (Secale cereale), wheat-rye hybrid (Triticale), common wheat (Triticum aestivum), oat (Avena sativa), rapeseed (Brassica napus), common sunflower (Helianthus annus) and flax (Linum usitatissimum).
References
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