t5 American beech

Allergens within Tree Pollens

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  • Latin name: Fagus grandifolia
  • Family: Fagaceae
  • Common names: American beech, Carolina beech, Gray beech, Red beech, Ridge beech, and White beech
  • Source material: Pollen

Allergen Exposure

Geographical distribution
The genus Fagus comprises 10 species of deciduous trees in the family Fagaceae, native to temperate Europe and North America. Fagaceae (Beech family), contains Beeches, Oaks, and Chestnuts.

Only American Beech is native to North America, ranging from southern Ontario to Nova Scotia, just west of the Mississippi to Texas, and south to the Gulf coast (1). In Europe this species is replaced with Common Beech (F. sylvatica). In Europe, Beech is indigenous only in England. Beech may be found in Armenia, Palestine, and Asia Minor. The southern beeches Nothofagus were previously thought to be closely related to beeches, but are now treated as members of a separate family, Nothofagaceae. They are found in Australia, New Zealand, New Guinea, New Caledonia and South America (2).

American Beech is a tall deciduous tree usually growing 20-25 m tall, although trees up to 40 m have been recorded. The crown is broad and the roots are wide spreading. The bark is smooth and blue- to light-grey. The leaves are yellow-green during the growing season. The 6 to 14 cm long leaves are leathery, oval, and yellow-green during the growing season. American beech leaves are finely toothed, whereas those of European beech have a wavy border (1).

The flowers are small single-sex (monoecious). The female flowers are borne in pairs. The male flowers are wind-pollinated catkins, produced in spring shortly after the new leaves appear. Male flowers occur in ball-like clusters on pendulous stalks. Female flowers are lesser in number, in leaf axils near the shoot tip. The Beech flowers in late spring. In the Northern Hemisphere, Beech pollen season extends from April to May. Beech trees are wind-pollinated. The European varieties shed more pollen than the native species. Beech pollen closely resembles oak pollen in morphology (1).

Beeches begin producing seed (fruit) when 40 years old, producing large quantities by 60 years of age. The fruit is a bur, usually containing two nuts. The fruit is a small, sharply three–angled nut 10-15 mm long, borne singly or in pairs in soft-spined husks 1.5–2.5 cm long, known as cupules (2). The pyramidal nuts are enclosed in pairs in a bristly husk. Seed is produced at 2- to 8-year intervals.

Beechnuts, called ’mast’ in England, are valued for feeding farm animals and may be roasted and eaten by humans or used a coffee substitute. Although edible, the nuts are bitter with a high tannin content.

Environment
American Beech occurs occasionally in woods and is sometimes cultivated. Beech wood is used to make parquet flooring, wood pavement, bentwood furniture, veneer plywood, and railroad ties (1). Coal tar used to protect wood from rotting is made from beech wood. Creosote, made from Beech wood, is used medicinally. The wood may be used for fuel. Dyes are made from the leaves and bark.

Allergens
To date no allergens have been characterised.

Potential cross-reactivity

High cross-reactivity is often found among different species within the same family. There is a relatively high degree of cross-reactivity between species of the family Fagaceae (3), and an extensive cross-reactivity within the genus Fagus has been demonstrated (4). There is strong cross-reactivity between Oak and members of the Birch family, Betulaceae (5).

Partial identity between the major allergens of Birch, Beech, Alder, Hazel and Oak pollen extract has been demonstrated by means of, among others, in vitro specific IgE tests (6).

Clinical Experience

IgE-mediated reactions
In studies on patients with seasonal rhinitis, it was found that Birch, Beech, Alder, Hazel, bog-myrtle and Oak pollens are most important as causes of springtime hay fever (7-8). However, Beech pollen does not play the most significant role in causing hay fever.

Rhinitis and asthma caused by exposure to Beech wood dust in wood workers has also been described (9-11). Furthermore, exposure to Beech dust may lead to the development of sore throat and bronchial hyperresponsiveness (12).

In a study in Westchester County in the state of New York of skin prick tests to 48 aeroallergens in100 patients referred for allergic rhinitis, 65% had a positive SPT to at least 1 aeroallergen of which 16% were positive to Beech (13). In an earlier study of hypersensitivity toward prevalent tree pollens in the New York area, the highest prevalence of hypersensitivity was for Oak (34.3%), Birch (32.9%), Maple (32.8%), American Beech (29.6%), Hickory (27.1%), Ash (26%), Elm (24.6%), and Poplar (20.6%) (14).

In Japan, investigation of stored sera demonstrated IgE antibodies directed at American beech tree (15).

Fagus spp. pollen has been recorded in the air of Bilecik in Turkey (16) and in Lublin (eastern Poland) (17). The pollen of Fagus spp. has also been reported in the air of Zurich (18).

Other reactions
Occupational contact allergy from Beech wood has been described (19).

Compiled by Dr Harris Steinman, harris@zingsolutions.com.

References:

    1. Weber RW. American beech. Ann Allergy Asthma Immunol 2004;92(5):A-6
    2. Wikipedia contributors, ”Beech”, Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Beech&oldid=224137905 (accessed July 14, 2008)
    3. Yman L. Botanical relations and immuno-logical cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09
    4. Eriksson NE, Wihl JA, Arrendal H, Strandhede SO. Tree pollen allergy. III. Cross reactions based on results from skin prick tests and the RAST in hay fever patients. A multi-centre study. Allergy 1987 Apr;42(3):205-14
    5. Weber RW. Cross-reactivity of plant and animal allergens. Clin Rev Allergy Immunol 2001;21(2-3):153-202
    6. Jung K, Schlenvoigt G, Jager L. Allergologic-immunochemical study of tree and bush pollen. III – Cross reactions of human IgE antibodies with various tree pollen allergens. [German] Allerg Immunol (Leipz) 1987;33(4):223-30
    7. Jung K, Schlenvoigt G, Jager L. Allergologic-immunochemical study of tree and bush pollen. II – Study of the sensitization spectrum of patients with seasonal rhinitis in the spring. Allerg Immunol 1987;33(4):215-21
    8. Eriksson NE. Allergy to pollen from different deciduous trees in Sweden. An investigation with skin tests, provocation tests and the RAST in springtime hay fever patients.
      Allergy 1978;33(6):299-309
    9. De Zotti R, Gubian F. Asthma and rhinitis in wooding workers.
      Allergy Asthma Proc 1996;17(4):199-203
    10. Hernandez M, Sanchez-Hernandez MC,
      Moreno V, Guardia P, et al. Occupational rhinitis caused by beech wood dust.
      Allergy 1999;54(4):405-406
    11. Williams PB. Critical analysis of studies concerning reports of respiratory sensitization to certain wood dusts.
      Allergy Asthma Proc 2005;26(4):4-267
    12. Bohadana AB, Massin N, Wild P, Toamain JP,
      Engel S, Goutet P. Symptoms, airway responsiveness, and exposure to dust in beech and oak wood workers.
      Occup Environ Med 2000;57(4):268-73
    13. Basak P, Arayata R, Brensilver J. Prevalence of specific aeroallergen sensitivity on skin prick test in patients with allergic rhinitis in Westchester County.
      Internet J Asthma Allergy Immunol 2008;6(2)
    14. Lin RY, Clauss AE, Bennett ES. Hypersensitivity to common tree pollens in New York City patients.
      Allergy Asthma Proc 2002;23(4):253-8
    15. Maeda Y, Ono E, Fukutomi Y, Taniguchi M, Akiyama K. Correlations between Alder Specific IgE and Alder-related Tree Pollen Specific IgE by RAST Method.
      Allergol Int 2008;57(1):79-81
    16. Türe C, Böcük H. Analysis of airborne pollen grains in Bilecik, Turkey. Environ Monit Assess 2008 Apr 23. [Epub ahead of print]
    17. Weryszko-Chmielewska E, Piotrowska K. Airborne pollen calendar of Lublin, Poland.
      Ann Agric Environ Med 2004;11(1):91-7
    18. Helbling A, Leuschner RM, Wüthrich B. Pollinosis. IV. Which pollens should be tested in allergology practice? Results of determinations of allergy-causing pollens in the Zurich air 1981-1984, with reference to threshold concentrations. [German] Schweiz Med Wochenschr 1985;115(34):1150-9
    19. Rasanen L, Jolanki R, Estlander T, Kanerva L. Occupational contact allergy from beechwood. Contact Dermatitis 1998;38(1):55

2008



Further Reading