Oak

Oak trees are one of the most prolific pollen producers in North America. A single oak tree can produce billions of pollen grains in a season. The yellow-green dust you see coating cars in spring is often oak pollen. Oak pollen grains are relatively small (20-30 micrometres), allowing them to travel hundreds of miles on wind currents.

If you're allergic to oak pollen, you may also react to:

• Birch (shared Bet v 1-like proteins)
• Chestnut
• Beech (same Fagaceae family)
• Apples, cherries, and hazelnuts (oral allergy syndrome)

• Oak season peaks in March-April — start antihistamines 2 weeks before.
• Pollen is heaviest in the morning. Schedule outdoor activities for late afternoon.
• The yellow coating on your car is largely oak pollen — wash it off regularly.
• Oak pollen cross-reacts with certain fruits. If your mouth itches after eating apples during oak season, this is oral allergy syndrome.