t207 Douglas fir
Allergens within Tree Pollens
- Latin name: Pseudotsuga taxifolia
- Family: Pinaceae
- Source material: Pollen
A tree species producing pollen, which often induces hayfever, asthma and conjunctivitis in sensitised individuals.
Allergen Exposure
Geographical distribution
Of the six species of Pseudotsuga, two are native to North America and four to Asia and parts of Europe.
The Douglas Fir tree is a tall evergreen timber tree, with short needles and egg-shaped cones similar to those of a Fir tree, but it is not a true Fir. Douglas Fir attains a height of 30 - 90m. Douglas Firs have irregularly whorled branches. The foliage is feathery-soft and not sharp. Colour varies from silver to heavy bluish-green. Branchlets are nearly smooth, but not as smooth as the branches of Firs.
Flowers are monoecious (individual flowers are either male or female, but both sexes are found on the same plant) and bloom in May. The fruit is a pendulous cone with three-lobed bracts extending beyond the cone scales. The fruit is very distinctive and is the best identification feature when present.
Environment
This is the most important timber tree of western North America, and is also widely planted in parts of Europe. The timber is usually called Oregon Pine or Yellow Fir.
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 (1).
Clinical Experience
IgE mediated reactions
Asthma, allergic rhinitis and allergic conjunctivitis, similar to reactions caused by other members of this family.
Other reactions
The Tussock Moth caterpillar in forested areas of Oregon was associated with itching of the skin and eyes, nasal discharge, cough, and, at times, respiratory difficulty in 41 of 428 individuals working in a forest (2).
References:
- Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09
- Press E, Googins JA, Poareo H, Jones K. Health hazards to timber and forestry workers from the tussock moth. Arch Environ Health 1977;32(5):206-210
2002