(HealthDay News) -- Hay fever -- an allergic reaction to pollen -- is what causes the runny eyes, sneezing, swelling and itching that makes you miserable when you head outside.

Hay fever worsens when outdoor trees, shrubs and other plants are pollinating, says the American Lung Association.

While anyone can have hay fever, it does tend to run in families, the association says. People who have been exposed to the pollens that trigger hay fever may quickly become more sensitive to these allergens.

The best thing you can do to prevent hay fever is to avoid the pollens that trigger it. Try to stay inside with an air conditioner and an air purifier running, and take an antihistamine to help manage symptoms. People with severe hay fever, if they need to be outdoors for long periods, should consider wearing a dust mask, the association says.