g204 False oat-grass

Allergens within Grass Pollens

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  • Latin name: Arrhenatherum elatius
  • Family: Poaceae (Gramineae)
  • Subfamily: Pooideae
  • Tribe: Aveneae
  • Common names: False Oat grass, Tall Oatgrass, Onion Couch
  • Source material: Pollen
There are two subspecies or varieties: one has swollen bases in the main shoots, like small onion bulbs, and is sometimes called 'Onion Couch'; the other lacks these swellings.
 
A grass species producing pollen, which often induces hayfever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution
False Oat grass is native to Europe and was brought to the United States early in the last century. It is now grown widely, for making hay and for grazing, in the central and northern states. World distribution includes the USSR, East Asia, and Africa.
 
It is a hardy, upright perennial bunchgrass growing up to 180 cm high, with many leaves scattered along the stems. The seed head resembles that of Oats: hence the name. The leaf blades, rolled in the bud shoot, are flat, linear, up to 50 cm long and 10 mm wide, and sometimes sparsely hairy.
 
The inflorescence is a panicle, green to purple, shining, erect or nodding, oblong or ovate, contracted, and up to 35 mm wide and 60 cm long. The hermaphrodite (containing both male and female organs) florets number 1 to 3 per spikelet. Incomplete (male) florets also occur at the base of the inflorescence. False Oat grass flowers from November in the Southern Hemisphere.
 
Environment
Often found in dry meadows or pastures, but very seldom in wild situations.
 
Allergens
No allergens from this plant have yet been characterised.

Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, as well as to a certain degree among members of the family Poaceae, particularly in the tribe Aveneae (Sweet Vernal grass (g1), Cultivated Oat (g14), Velvet grass (g13), Canary grass (g71)) (1-2). 

Clinical Experience

IgE mediated reactions
False Oat grass pollen may induce asthma, allergic rhinitis and allergic conjunctivitis.
 
Compiled by Dr Harris Steinman, harris@zingsolutions.com

References:

    1. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09 
    2. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000

2002



Further Reading