Thommen's Postulates
Try repeating this three times fast and you will end up tongue tied. Just what is Thommen's Postulates? Proposed in 1931 by A.A. Thommen, it is five characteristics a pollen must have to be considered allergenic (causing hay fever symptoms).

• The pollen must contain excitant of hay fever.
• The pollen must be produced in sufficiently large quantities
• The pollen must be anemophilus (airborne).
• The pollen must be buoyant enough to be carried long distances.
• The plant which produces the pollen must be widely and abundantly distributed.

Thommen's Postulates, which have been around for 80 years, are still quite accurate in providing guidance on what pollen is allergenic and what isn't. However, there are a few caveats. For example, while insect distributed pollen in general is sticky and heavy, and not easily wind borne, some primarily insect-pollinated plants will release sufficient airborne pollen to cause sensitization in the proper setting, such as a flowering tree or shrub situated at a bedroom window.

If a pollen meets all five characteristics one can be fairly certain it is going to be allergenic. Ragweed, Oak, and Timothy all pass the test and are extremely potent allergenic pollens. So when a patient says I think I am allergic to my tulip flowers, put it to the Thommen's test!

Until next time,
Larry Garner, NAC