What is pollen?

Pollen is a fine yellow powder. It is made of the male reproductive cells of flowering plants, trees, grasses, and weeds. Pollen is tiny (microscopic). It is the most common cause of hay fever (seasonal allergic rhinitis).

Which plants make pollen that cause allergic reactions?

Plants that spread their pollen by the wind are the most common cause of allergic rhinitis. They include:

• Trees. These include oak, western red cedar, elm, birch, ash, hickory, poplar, sycamore, maple, cypress, walnut, catalpa, olive, and pecan.

• Grasses. These include timothy, Johnson, Bermuda, orchard, sweet vernal, red top, and some bluegrasses.

• Weeds. These include ragweed, sagebrush, pigweed, tumbleweed, Russian thistle, and cockleweed.

The pollen of most flowering plants, such as roses, is heavier, waxy, and spread by insects. These plants generally do not trigger allergies.

When is pollen season?

Each type of plant has a pollen season. Some plants bloom in the spring, others bloom in the fall. Pollen season often starts in the spring. But it may begin as early as January in the western U.S. The season often lasts until November.

Can allergic rhinitis in pollen season be prevented?

To reduce the effects of allergic rhinitis during pollen season, do the following:

• Keep windows closed during pollen season. And use air conditioning with a HEPA filter. This cleans, cools, and dries the air.

• Reduce outdoor activities early in the morning between 5 a.m. and 10 a.m. This is when pollen is most common.

• Keep car windows closed when traveling.

• Take vacations in areas where pollen is not as common, such as the ocean.

• Give your child his or her medicines, as prescribed by the healthcare provider.

• Reduce your child's time spent outdoors when the pollen count is high.

• Bathe and shampoo your child's hair after playing outside. Wash clothes that were worn outside.

• Don't rake leaves or have your child jump in piles of raked leaves during pollen season.

• Don't hang your child's bedding or clothing outside to dry.

• Have your child wear sunglasses and a hat when outside. This helps keep pollen out of their eyes and hair.

• Talk with your child's healthcare provider about allergy shots (immunotherapy) for your child. These can give long-term symptom relief. They help your child's body build up a resistance to pollen.